Recipe for Lemon Posset: 3 Ingredient British Dessert with Sugar-Free Option
Lemon posset is one of those desserts that makes you look like a far better cook than the effort involved. Three ingredients. Eight minutes on the stove. No baking, no eggs, no gelatin. You pour it into ramekins or hollowed out lemon shells, walk away and the fridge does all the work. A few hours later you have a silky, set cream dessert with a bright lemon flavor that honestly rivals anything you would get at a nice restaurant. This recipe for lemon posset is a little different since you and save alot of calories and sugar withe the keto and sugar free lemon posset variation.
I first came across lemon posset while researching British desserts and was skeptical that something this simple could actually be this good. It can. The science behind it is almost magical. The acid in the lemon juice reacts with the proteins in the cream, causing it to thicken and set without any traditional thickeners. Once I made my first batch I understood why this has been a beloved dessert in England for centuries.
Even better, lemon posset is naturally very close to keto as it is. Heavy cream and lemon juice are already low carb staples. The only thing standing between a traditional posset and a keto posset is the sugar. Swap it for allulose and you have an elegant sugar-free dessert that tastes identical to the original. I have included both versions below so you can make whichever fits your goals but the allulose version was honestly a big hit. I tested it at a small dinner party and everyone raved about it without knowing it was sugar free!
Speaking of the dinner party, we had a whole conversation about the pronunciation of this dessert. Since it's an English creation, it's pronounced with the “t” at the end rather than the POSS AY French pronunciation, although either is technically acceptable (at least according to Julien).
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What Is Lemon Posset
A posset is a traditional British dessert made from cream, sugar and citrus juice. It dates back over 600 years to medieval England where it originally started as a warm drink made from curdled milk mixed with wine or ale. People believed it had healing properties and it was commonly served as a remedy for colds. Shakespeare even mentioned possets in his plays.
The modern version we know today is quite different from that old warm drink. It is a cold set cream dessert with a texture somewhere between panna cotta and a rich pudding. Think of it as a creamier, more delicate version of lemon curd. What makes it special is that it sets entirely through the chemical reaction between the acid in the citrus juice and the proteins in the cream. No eggs. No cornstarch. No gelatin. Just science doing its thing in your fridge.
While lemon is by far the most popular flavor, you can make posset with any citrus that is acidic enough to trigger the setting reaction. Lime, blood orange and grapefruit all work beautifully. The key is using enough acid relative to the amount of cream.
Why This Recipe Works
I have tested a lot of lemon posset recipes and landed on this ratio because it produces the best texture every single time. Here is what makes this version reliable.
The cream-to-acid ratio is dialed in. Too little lemon juice and it will not set. Too much and you get a grainy texture. One-third cup of juice to two cups of cream hits the sweet spot for a silky set that holds its shape on a spoon without being too stiff.
Boiling the cream matters. This is not just about dissolving the sugar. Boiling the cream for a full five minutes reduces it slightly and helps the proteins denature, which is essential for setting. If you skip this step or cut it short you will end up with a posset that never fully thickens.
Straining is non-negotiable. The lemon zest adds incredible flavor while the cream simmers but leaving it in creates a slightly lumpy texture. Straining through a fine mesh sieve after adding the juice gives you that perfectly smooth, velvety finish.
The keto swap is seamless. Because posset relies on the cream-acid reaction for structure rather than sugar for body, you can replace the sugar with allulose without changing the method or the texture. This is one of the rare desserts where the keto version genuinely tastes the same as the original.
Ingredients You Need
The beauty of lemon posset is the short ingredient list. You likely have everything in your kitchen right now.
Heavy cream. Use heavy whipping cream with at least 36 percent fat content. This is the foundation of the dessert and lighter creams like half-and-half or light cream will not set properly. Do not substitute. Heavy cream is naturally a keto pantry staple with less than one gram of carbs per tablespoon.
Sugar (classic version) or allulose (keto version). Granulated white sugar works perfectly for the traditional recipe. For the keto version I use allulose because it dissolves cleanly, does not crystallize in the fridge and measures cup for cup like regular sugar. More on sweetener options below.
Lemons. You need both the zest and the juice. Plan on two to three medium lemons to get one tablespoon of zest and 1/3 cup of juice. Always zest before you juice because it is nearly impossible to zest a squeezed lemon. Fresh juice is essential here. Bottled lemon juice has a different acidity level and can produce inconsistent results.
Classic Lemon Posset Recipe
This is the traditional version made with sugar. If you are following a keto or low carb diet, scroll down to the keto version below. Both work exceptionally well!
Ingredients
- 2 cups heavy whipping cream
- 2/3 cup granulated sugar
- 1 tablespoon lemon zest (about two lemons)
- 1/3 cup fresh lemon juice (about two to three lemons)
Optional garnishes: fresh berries, a small dollop of whipped cream, a sprig of mint or additional lemon zest.
Instructions
1. Prep the lemons. Zest the bottom halves of the lemons first until you have one tablespoon of finely grated zest, avoiding the bitter white pith. Then cut lengthwise (if serving in the lemon halves) and juice them and remove the skin from the halves until you have 1/3 cup of juice. Set both aside separately.
2. Boil the cream. In a medium saucepan, combine the heavy cream, sugar and lemon zest. I also added the lemon juice in this step, but some say to wait. Bring to a boil over medium-high heat, stirring frequently to dissolve the sugar. and manage the boil. Use a larger pot than you think you need because the cream will foam up aggressively and it loves to boil over, don't leave the stove while this is cooking or you're likely to have a mess.
3. Reduce. Once boiling, reduce the heat slightly and maintain a steady boil for eight minutes, stirring frequently. Adjust the heat as needed to keep the cream from climbing out of the pot. The mixture should reduce just slightly.
4. Add the lemon juice. Remove the pan from the heat and stir in the 1/3 cup of lemon juice if you didn't already. You will notice the mixture start to thicken almost immediately. This is the acid reacting with the cream proteins. That is exactly what you want.
5. Cool and strain. Let the mixture sit at room temperature for 15 to 20 minutes. Then pour through a fine mesh sieve into a bowl or large measuring cup, pressing gently to extract all the liquid. Discard the zest solids.
6. Pour and chill. Divide evenly among six small ramekins, lemon halves, glasses or cups. Each serving is about 1/3 cup. Refrigerate uncovered for at least three hours or until fully set. You can also make these the night before and cover with plastic wrap once set.
7. Garnish and serve. Top with fresh berries, a tiny bit of whipped cream or a pinch of extra lemon zest. Keep portions small. This is a rich dessert and a little goes a long way.
Classic version nutrition (per serving, serves 6): approximately 350 calories, 29g fat, 24g carbohydrates, 22g sugar, 2g protein.
The following is the exact same recipe with one swap. Replace the sugar with allulose and you have a keto lemon posset that is absolutely indistinguishable from the original. Because the setting reaction comes from the cream and lemon juice rather than from the sugar, the texture stays the same. With the calorie savings and the exact same taste, I highly recommend the keto lemon posset version even if you're not trying to keep a low carb diet.
Keto Lemon Posset Recipe (Sugar Free)
Ingredients
- 2 cupes heavy cream
- ⅔ cup allulose
- ⅓ cup fresh lemon juice
- 1 tablespoon lemon zest
Instructions
- Prep the lemons. Zest the bottom halves of the lemons first until you have one tablespoon of finely grated zest, avoiding the bitter white pith. Then cut lengthwise (if serving in the lemon halves) and juice them and remove the skin from the halves until you have 1/3 cup of juice. Set both aside separately.
- Boil the cream. In a medium saucepan, combine the heavy cream, allulose and lemon zest. I also added the lemon juice in this step, but some say to wait. Bring to a boil over medium-high heat, stirring frequently to dissolve the sugar. and manage the boil. Use a larger pot than you think you need because the cream will foam up aggressively and it loves to boil over, don't leave the stove while this is cooking or you're likely to have a mess.
- Reduce. Once boiling, reduce the heat slightly and maintain a steady boil for eight minutes, stirring frequently. Adjust the heat as needed to keep the cream from climbing out of the pot. The mixture should reduce just slightly.
- Add the lemon juice. Remove the pan from the heat and stir in the 1/3 cup of lemon juice if you didn't already. You will notice the mixture start to thicken almost immediately. This is the acid reacting with the cream proteins. That is exactly what you want.
- Cool and strain. Let the mixture sit at room temperature for 15 to 20 minutes. Then pour through a fine mesh sieve into a bowl or large measuring cup, pressing gently to extract all the liquid. Discard the zest solids.
- Pour and chill. Divide evenly among six small ramekins, lemon halves, glasses or cups. Each serving is about 1/3 cup. Refrigerate uncovered for at least three hours or until fully set. You can also make these the night before and cover with plastic wrap once set.
- Garnish and serve. Top with fresh berries, a tiny bit of whipped cream or a pinch of extra lemon zest. Keep portions small. This is a rich dessert and a little goes a long way.
Video
Equipment
Nutrition
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Keto version nutrition (per serving, serves 6): approximately 273 calories, 28g fat, 3g net carbs (from the lemon juice and cream), 2g protein. The allulose does not count toward net carbs because your body does not metabolize it for energy. If you are new to allulose, I talk more about it in our keto food list where I break down the best sweetener options.
Why allulose works best here. Allulose is the clear winner for posset. It dissolves completely, does not crystallize in the fridge (a common problem with erythritol-based sweeteners) and has no cooling aftertaste. It measures cup for cup like regular sugar so you do not need to do any conversion math. Plus allulose really is the best alternative sweetener choice. If you are tracking macros with our free keto calculator, allulose is listed at zero net carbs.
How to Serve Lemon Posset in Lemon Shells
Serving lemon posset inside hollowed out lemon halves is a beautiful presentation that has become hugely popular for good reason. It looks stunning and it is actually quite simple to pull off.
How to prep the lemon shells:
Choose large lemons with thick rinds since they hold their shape better. Cut each lemon in half lengthwise. To do it super cleanly, use a paring knife to carefully cut around the inside edge of the pith, then use a spoon to scoop out all the pulp and membrane. Or you can be lazy like I was and just scoop it out with a spoon, but you will need to pull out excess skin. In the video I left more in than I probably hsould have for presentation purposes, but actually having a little bit of fresh lemon left in the rind to scrape of with the custard tasted great!
Reserve the juice for the recipe by pressing the pulp through a sieve. You can also slice a tiny bit off the bottom of each half so it sits flat without wobbling.
This recipe fills 10 to 12 lemon halves depending on the size of your lemons. Place the shells in a muffin tin to keep them stable while filling and chilling if you don't cut the bottoms. Pour the strained posset mixture directly into the shells and refrigerate for at least three hours.
The lemon shell presentation is perfect for dinner parties, Easter brunch, baby showers or any spring gathering where you want an elegant dessert that you can make entirely ahead of time.
Lemon Posset Brulee Variation
If you want to take your lemon posset up a notch, adding a brulee top turns it into something truly special. The contrast of the warm, crackly caramelized sugar against the cold, creamy posset underneath is incredible.
For the classic version: Once the posset is fully set and chilled, sprinkle about one teaspoon of granulated sugar evenly over the top of each serving. Use a kitchen torch to caramelize the sugar until it is golden and bubbling. Let it sit for about 30 seconds to harden before serving.
For the keto version: Use allulose for the brulee top as well. Allulose caramelizes beautifully, which is one reason pastry chefs love it. Sprinkle one teaspoon of granulated allulose over each set posset and torch it the same way. It browns and crisps just like sugar. Erythritol-based sweeteners do not caramelize well and are not recommended for the brulee top.
A kitchen torch is a worthwhile investment that costs under $20. I use mine for brulee, for finishing meats and for charring peppers. If you do not have a torch you can place the ramekins under a broiler set to high for two to three minutes, watching very closely.
Troubleshooting: Why Your Lemon Posset Did Not Set
Lemon posset is forgiving but there are a few things that can go wrong. If your posset did not set properly, one of these is almost certainly the reason.
You did not boil the cream long enough. This is the most common issue. The cream needs a full eight minutes at a steady boil to reduce slightly and denature the proteins enough for the acid to set the mixture. If you pulled it off the heat too early, pour it back into the pot and boil for a couple more minutes before adding the lemon juice.
You did not use enough lemon juice. One-third cup is the minimum for two cups of cream. If your lemons were small or not very juicy you may have come up short. Always measure the juice rather than going by number of lemons since they vary widely.
You used bottled lemon juice. Bottled juice has a different acidity profile than fresh and does not always trigger the setting reaction reliably. Fresh lemons are worth the extra minute of effort.
Your cream was too light. Heavy whipping cream with at least 36 percent fat is essential. Half-and-half, light cream or whipping cream with lower fat content simply will not set. There is not enough protein and fat for the acid to work with.
You did not chill it long enough. The posset needs a minimum of three hours in the refrigerator. Overnight is even better. If it has only been a couple of hours and it still looks loose, give it more time before panicking.
Sweetener crystallization (keto version). If you used an erythritol-based sweetener like Swerve, you may notice a gritty layer forming on top after several hours in the fridge. This is erythritol recrystallizing. It is harmless but affects the texture. This is the main reason I recommend allulose instead. It stays smooth no matter how long the posset sits in the refrigerator.
Sweetener Guide for the Keto Lemon Posset Version
Not all keto sweeteners behave the same in a cold-set dessert like posset. Here is what I have found through testing.
Allulose (recommended). Dissolves completely, does not crystallize in the fridge, no aftertaste and caramelizes if you want to brulee the top. Measures cup for cup like sugar. This is my go-to for posset and most keto desserts. There are even some studies suggesting allulose may help lower blood glucose, which I discuss in the keto food list.
Monk fruit blend (backup option). A granulated monk fruit and allulose blend works well as an alternative. Check the package to see if it measures one-to-one with sugar since some blends are concentrated. Pure monk fruit extract is extremely sweet and not suitable for this recipe without a blend.
Erythritol or Swerve (not ideal). These dissolve during cooking but tend to recrystallize as the posset chills, creating a gritty texture on the surface. If this is all you have on hand it will work but the texture will not be as smooth as allulose. Confectioners Swerve performs slightly better than granulated for this reason.
Stevia and liquid sweeteners (not recommended). Liquid sweeteners change the cream-to-liquid ratio which can affect setting. Stevia can also have a bitter aftertaste that becomes more noticeable in a dessert this simple with so few competing flavors.
Frequently Asked Questions
How Many Calories Are in Lemon Posset?
The classic sugar version has approximately 350 calories per serving when divided into six portions. The keto version made with allulose has approximately 265 calories per serving because allulose contributes minimal metabolizable calories. Either way this is a rich dessert and small portions are the way to go.
Can I Make Lemon Posset With Condensed Milk?
Traditional lemon posset is made with heavy cream and does not use condensed milk. Some people make a different lemon dessert by combining condensed milk with lemon juice which creates a similar set texture but the flavor and richness are quite different. If you want the authentic posset experience, stick with heavy cream. If you are looking for a keto version, condensed milk is very high in sugar and carbs so it would not be a good fit.
Can Lemon Posset Be Made Dairy Free?
Unfortunately no. The entire setting mechanism depends on the interaction between the fat and protein in heavy cream and the acid in the lemon juice. Coconut cream does not contain the same proteins and will not set the same way. You could try adding gelatin to coconut cream with lemon juice for a similar dessert but it would technically be a panna cotta rather than a posset.
How Far in Advance Can I Make Lemon Posset?
You can make lemon posset up to two days ahead of time. It actually benefits from an overnight chill because the flavor develops and the texture firms up. Cover with plastic wrap once fully set and keep refrigerated. Add garnishes just before serving. This make-ahead quality is one of the reasons posset is such a great dessert for entertaining.
Can I Freeze Lemon Posset?
Freezing is not recommended because the texture changes significantly when thawed. The cream can become grainy and separate. If you need to store leftovers beyond two days you can freeze them, but expect a softer and slightly less smooth texture after thawing in the fridge.
Is Lemon Posset Keto Friendly?
The traditional version made with sugar is not keto friendly because the sugar adds about 22 grams of carbs per serving. However the keto version made with allulose comes in at approximately 2 net carbs per serving, all from the lemon juice and cream. Heavy cream and lemons are both keto-approved foods which is why this dessert converts so well.
What Is the Difference Between Lemon Posset and Panna Cotta?
Both are chilled cream desserts but they set through different mechanisms. Panna cotta uses gelatin to set while lemon posset sets through the chemical reaction between the acid in citrus juice and the proteins in cream. Posset has a denser and slightly richer texture than panna cotta and a pronounced citrus flavor. Panna cotta is typically more neutral and jiggly.
Can I Use Lime or Other Citrus Instead of Lemon?
Yes. Any citrus juice that is acidic enough will work. Lime posset is excellent and you can also try blood orange, grapefruit or a combination. The key is maintaining the same amount of juice, about 1/3 cup for two cups of cream. Sweeter citrus like regular orange may not have enough acid to set the posset properly on its own so you may need to supplement with a tablespoon or two of lemon juice.
Looking for more dessert ideas that fit a low carb lifestyle? Browse all of our keto recipes for more inspiration.
