Anna Louise Lemon posset is the dessert that makes professional pastry chefs look over their shoulders. Three ingredients — double cream, caster sugar, and fresh lemon juice — no gelatine, no eggs, no baking, no technical skill.
And yet the result is one of the most elegant, most delicious desserts in British cooking — a silky, slightly trembling, intensely lemony cream that sets to a consistency somewhere between a mousse and a pannacotta and tastes completely extraordinary.
Mary Berry’s lemon posset recipe is the simplest version of this ancient British dessert. It is practically foolproof, can be made the day before, looks beautiful in small glasses, and impresses everyone who eats it without requiring more than fifteen minutes of active work.
The chemistry is beautiful — the acid in the lemon juice causes the proteins in the cream to tighten and set, without any gelatine or eggs required.
It is one of the most elegant demonstrations of cooking chemistry that exists, and it produces something that tastes as if it must have taken far longer than it did.
How Does Lemon Posset Set Without Gelatine?
Lemon posset sets through the interaction of acid and protein. Double cream contains proteins — caseins — that are disrupted by acid. When the lemon juice is added to the hot cream and sugar mixture, the acid causes these proteins to denature and tighten, creating a gel-like structure that sets the cream as it cools.
This is why the quality and quantity of lemon juice matters so much. Too little acid and the posset does not set firmly enough. Too much and it can become slightly grainy or over-set.
The ratio in this recipe — 80ml of lemon juice to 600ml of double cream — is calibrated for a perfectly set, silky posset.
Ingredients for Mary Berry Lemon Posset
- 600ml double cream
- 150g caster sugar
- Juice of 3 large lemons (approximately 80ml) — always freshly squeezed
- Finely grated zest of 2 of the lemons (optional — gives a more fragrant posset)
To Serve
- Fresh raspberries or blueberries
- Thin shortbread biscuits alongside
- A small sprig of fresh mint
- A curl of lemon zest
How to Make Mary Berry Lemon Posset — Step by Step
Step 1 — Heat the Cream and Sugar
Pour the double cream into a medium saucepan. Add the caster sugar and lemon zest if using. Heat over a medium heat, stirring occasionally, until the sugar has completely dissolved and the cream is hot and just beginning to simmer at the edges.
Once simmering, let it bubble gently for exactly three minutes — stir regularly to prevent it from boiling over. Do not let it boil vigorously. A gentle three-minute simmer is exactly right.
Step 2 — Add the Lemon Juice
Remove the pan from the heat. Add the freshly squeezed lemon juice all at once and stir gently to combine. The mixture will thin slightly when the lemon juice is added — this is normal. It sets as it cools.
Step 3 — Pour Into Glasses
Leave the posset to cool for five minutes — just enough for the surface foam to settle. Pour carefully through a fine sieve into six small glasses, ramekins, or cups — the sieve catches the lemon zest and any surface foam.
Fill each vessel to about two-thirds full — the posset needs a little headroom for the fruit topping.
Step 4 — Set Overnight
Cover each glass loosely with cling film and refrigerate for at least four hours — overnight is significantly better. The posset will set from a liquid to a slightly trembling, silky, almost solid consistency as it chills.
Step 5 — Serve
Remove from the fridge twenty minutes before serving. Top each posset with a few fresh raspberries or blueberries. Add a small sprig of mint and a curl of lemon zest. Serve with thin shortbread biscuits alongside.
My Top Tips For Mary Berry Lemon Posset
Use fresh lemon juice — always. This recipe has three ingredients. The quality of each one is directly apparent in the finished posset. Bottled lemon juice gives a flat, slightly artificial result. Fresh lemons give the bright, vivid flavour that makes lemon posset so extraordinary.
Measure the lemon juice accurately. The acid-to-cream ratio is what makes posset set. 80ml of lemon juice to 600ml of cream is the calibrated ratio for this recipe. Too little lemon and the posset does not set. Too much and it can over-set or become slightly grainy.
Simmer for exactly three minutes. Not two, not five — three minutes at a gentle simmer reduces the cream slightly and ensures the proteins are in the right state to respond to the acid. Time it.
Add lemon juice off the heat. Adding the lemon juice to cream still on the heat can cause it to curdle slightly. Remove from the heat before adding the juice.
Refrigerate overnight for the best set. Four hours gives a reasonable set. Overnight gives a silky, perfectly firm posset that unmoulds cleanly if desired and holds its shape beautifully when a spoon is dipped in.
Serve with shortbread. The buttery, slightly crumbly texture of a thin shortbread against the silky, sharp lemon posset is one of the great dessert pairings. Always include a shortbread biscuit alongside.
Serving Suggestions
In small glasses or ramekins with fresh raspberries and shortbread — the classic and perfect presentation. As a dinner party dessert — it can be made two days ahead, requires no last-minute work, and looks genuinely beautiful. As a simple weeknight pudding when you want something special that takes ten minutes to prepare.
How to Store Mary Berry Lemon Posset
In the fridge: Store covered for up to 3 days. The posset stays silky and the flavour remains bright.
Freezing is not recommended — the texture of posset suffers when frozen and defrosted.
Mary Berry Lemon Posset Recipe
Ingredients
Method
- Place cream, sugar, and lemon zest in a medium saucepan. Heat over medium heat, stirring, until sugar dissolves and cream begins to simmer at the edges.
- Simmer gently for exactly 3 minutes, stirring regularly. Do not boil vigorously.
- Remove from heat. Add lemon juice all at once. Stir gently to combine.
- Cool 5 minutes. Pour through a fine sieve into 6 small glasses or ramekins.
- Cover loosely with cling film. Refrigerate overnight minimum.
- Remove from fridge 20 minutes before serving. Top with fresh berries, mint, and lemon zest. Serve with shortbread alongside.
Notes
Frequently Asked Questions
Can I make lemon posset with lime or orange?
Yes — lime posset is extraordinary. Use the same quantity of fresh lime juice (approximately 80ml) and the zest of two limes. The result is more floral and slightly more complex than lemon. Orange posset is less sharp and sweeter — reduce the sugar to 100g and use 90ml of fresh orange juice.
Why has my posset not set?
Either the lemon juice quantity was too small, the cream was not simmered for long enough, or the posset was not given enough time in the fridge. Check all three. If it has been in the fridge for twelve hours and is still liquid, it will not set further.
Can I make a larger batch?
Yes — double all quantities and pour into twelve glasses. The technique and timing remain exactly the same.
Can I add other flavourings?
Yes — a teaspoon of vanilla extract added with the cream gives a vanilla-lemon posset that is very good. Lavender posset — made by infusing the cream with fresh lavender before straining and proceeding — is exceptional. A few drops of elderflower cordial stirred in at the end gives a floral, summery variation.
Can I unmould the posset?
If set overnight in ramekins lightly greased with a neutral oil, the posset can be unmoulded onto a small plate by running a knife around the edge and inverting. It looks dramatic and elegant. Make sure it has set overnight before attempting.
Why is my posset grainy?
Either too much lemon juice was added, the cream was boiled too vigorously, or the lemon juice was added while the cream was still on the heat. Follow the recipe quantities precisely and add the juice off the heat.
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