The molten centre here is not underbaked batter. It is lemon curd, cooked on the stove to 160°F, spooned into six mounds and frozen until firm.
Each frozen core is sealed between two layers of a vanilla butter-cake batter in a buttered ramekin. In twelve to fourteen minutes at 400°F the edges set and the curd melts back into a sauce.
Why the Centre Is Safe to Eat Runny
The soft centre is cooked before it is ever baked.
- CurdYolks, sugar, lemon juice and zest whisked over medium-low heat.
Check before you continue
160°F — Instant-read thermometer
The curd thickens and reaches 160°F before the butter goes in.
- FreezeSix mounds on parchment, about 30 minutes.
- BakeBuried in batter, 12 to 14 minutes at 400°F.
How to Make It
Curd cooked to 160°F
Whisk the egg yolks, 1/2 cup sugar, lemon juice and zest in a saucepan over medium-low heat until thickened and the mixture reaches 160°F. Remove from the heat and whisk in the 4 tbsp butter.
Curd frozen
Spoon the lemon curd into 6 small mounds on parchment and freeze until firm, about 30 minutes.
Ramekins buttered
Heat oven to 400°F and butter six 6-oz ramekins.
Batter
Whisk the flour, baking powder and salt. Beat 1/2 cup butter with 2/3 cup sugar, then beat in the eggs and vanilla. Fold in the dry ingredients, alternating with the milk.
Cores buried
Fill the ramekins halfway, place one frozen lemon-curd core in each and cover with the remaining batter.
Baked
Bake 12 to 14 minutes until the edges are set and the centres remain soft.
Turned out
Rest 2 minutes, invert carefully and dust with powdered sugar.
Why This Recipe Works
- Cooking the curd fully first means the soft centre is safe as well as runny.
- Freezing the curd lets the batter set around it before it melts.
- A hot oven and a short bake keep the centre liquid.
- Resting two minutes lets the cakes release from the ramekins.
Ingredient Notes
- Fresh lemon juice and zest
- A third of a cup of juice and a tablespoon of zest, all in the curd.
- Egg yolks
- Three, cooked into the curd to 160°F before it is frozen.
- 6-oz ramekins
- Six, buttered well so the cakes turn out.
Success Tips
- Whisk the curd without stopping so the yolks thicken evenly.
- Keep the curd cores in the freezer until the batter is ready.
- Make sure each core is fully covered by batter on top.
Serving Ideas
Turn each cake out onto a plate, dust with powdered sugar and add a lemon slice and a raspberry beside it.
Storage and Reheating
Refrigerate
Serve straight from the oven; the curd firms up as the cakes cool.
Frequently Asked Questions
Is the runny centre raw?
No. It is lemon curd cooked to 160°F before it is frozen and baked inside the cake.
Can the curd be made ahead?
The cores are frozen until firm, about 30 minutes, and stay frozen until they go in.
