Mary Berry Lemon Posset Tart

This tart is one of those deceptively simple desserts that makes people think you’ve been in the kitchen all day. I made it for a Sunday lunch once when I’d completely forgotten pudding—and thank goodness lemons and cream are always in my fridge. It set perfectly, sliced cleanly, and the balance of sweet and sharp was bang on.

The first time I made it, though, I was too eager and poured the lemon mix into the pastry while it was still warm. Big mistake. The base went soggy and the tart didn’t slice properly. Since then, I let everything cool fully—and it’s been flawless every time.

THE SECRET BEHIND THIS BAKE

What makes this tart sing is the simplicity of the posset filling. Just cream, sugar, and lemon—but when heated and stirred correctly, the lemon thickens the cream into a dreamy, sliceable custard. No eggs, no gelatine, no faff.

And the pastry? It’s buttery, short, and crisp—especially if you chill it well and bake it blind. Top with raspberries just before serving and it becomes something special.

INGREDIENTS + WHY THEY MATTER

For the pastry:

• Plain flour (175g) – Standard base. Don’t skip the dusting flour—it prevents sticking.
• Cold butter (75g) – Must be cold for that classic crumbly shortcrust.
• Icing sugar (1 tbsp) – Adds a light sweetness without grittiness.
• Egg (1, beaten) – Binds the dough together for rolling.

For the lemon filling:

• Double cream (600ml) – Gives richness and helps the tart set without eggs.
• Caster sugar (150g) – Dissolves easily and balances the tart lemon.
• Lemon zest & juice (from 3 lemons) – Always use fresh! Bottled juice won’t set or taste as sharp.

To serve:

• Raspberries (250g) – Adds freshness and colour.
• Icing sugar (for dusting) – Optional, but pretty.

MAKING IT YOURS (WITHOUT RUINING IT)

• No raspberries? Blueberries or sliced strawberries also work.
• Want a crunch? Add a thin layer of crushed amaretti or biscuit crumbs under the filling.
• Short on time? Use a good-quality shop-bought pastry case (I won’t tell).
• Need it dairy-free? Unfortunately, no tested swaps work for this one—it needs the fat in double cream to set.

MISTAKES I’VE MADE (AND HOW TO AVOID THEM)

What Went Wrong	Why It Happens	How to Fix It
Soggy pastry base	Filled with hot lemon mixture	Let filling cool for 5+ minutes before pouring
Pastry shrank in oven	Didn’t chill it long enough	Chill at least 30 minutes after lining the tin
Filling didn’t set	Used bottled lemon juice	Always use fresh lemons—they activate the cream
Filling overflowed	Overfilled the tart case	Leave a bit of space at the top—it spreads

HOW TO MAKE MARY BERRY’S LEMON POSSET TART

1. Preheat and prepare
   Preheat oven to 200°C/180°C fan/Gas 6. Grease and line a 20cm round, deep loose-bottomed tin.
2. Make the pastry
   Blend flour, butter, and icing sugar to breadcrumbs in a food processor. Add egg and mix to a dough. Or rub by hand and stir in the egg.
3. Roll and chill
   Roll dough thinly on a floured surface. Line the tin, trim edges, prick base. Chill in fridge for 30 minutes.
4. Bake the pastry blind
   Line with baking paper, fill with beans. Bake 15 mins. Remove paper and beans, bake 5–7 mins more until golden. Cool completely.
5. Make the filling
   In a saucepan, gently heat cream, sugar, and zest. Bring just to a boil, stirring. Remove from heat and cool 5 minutes. Stir in lemon juice—mixture will thicken slightly.
6. Fill and chill
   Pour the cooled lemon mixture into the pastry case. Chill for at least 4 hours, preferably overnight.
7. Serve
   Top with raspberries and dust with icing sugar. Slice with a hot knife for clean edges.

TIPS FROM MY KITCHEN

• I use a microplane for zest—super fine, no bitter pith.
• I place the tart on a tray before pouring in the filling—it’s easier to transfer to the fridge.
• I serve it cold with a jug of pouring cream on the side.

STORAGE + SERVING

• Keeps – Up to 3 days in the fridge in a sealed container.
• Freezes – Not recommended—the filling doesn’t hold its texture.
• Serve with – Fresh berries, pouring cream, or a dusting of icing sugar.

FREQUENTLY ASKED QUESTIONS

Q: Can I use shop-bought pastry?
A: Yes! Just blind bake as you would homemade. Saves loads of time.

Q: Can I make this in advance?
A: Definitely—it’s best made the day before so the filling sets fully.

Q: Why did my filling not set?
A: Likely the lemon juice wasn’t fresh or the cream didn’t boil fully. Both are key to the posset thickening.

Q: Can I use limes instead?
A: I’ve tried it—it’s nice, but lime is milder. Use 4 limes instead of 3 lemons for similar zing.

Try More Recipes:

• Mary Berry Lemon Tart With Lemon Passion Fruit Curd
• Mary Berry Granny’s Little Shortbread Biscuits
• Mary Berry St Clements Creams