Ingredients
Equipment
Method
Step 1 – Prepare your pan and oven.
- Preheat the oven to 325°F (160°C). Grease and line an 8x8-inch square baking pan with parchment paper.
Step 2 – Whip the egg whites.
- In a clean bowl, beat egg whites until stiff peaks form. Set aside. This helps create the sponge top.
Step 3 – Mix the yolk batter.
- In another bowl, whisk egg yolks with sugar until pale. Add melted butter, vanilla, lemon juice, and zest. Mix until smooth.
Step 4 – Add the flour and milk.
- Gently whisk in the flour, then slowly add warm milk, mixing until you have a thin batter.
Step 5 – Fold in egg whites.
- Fold whipped egg whites into the batter in three parts. The mixture will look lumpy and uneven, but that’s exactly how it should be.
Step 6 – Bake.
- Pour the batter into your prepared pan and bake for 50–60 minutes, until the top is golden and set. The center will still jiggle slightly.
Step 7 – Cool and set.
- Let the cake cool to room temperature, then chill in the fridge for at least 2 hours before slicing. Dust with powdered sugar before serving.
Notes
Tips & Tricks
- Separate eggs carefully. Even a tiny bit of yolk in the whites can stop them from whipping properly.
- Use warm milk. Cold milk can prevent the layers from separating into sponge, custard, and base.
- Don’t overmix. The batter should look slightly lumpy after folding in the egg whites. That’s how you get the magic layers.
- Bake low and slow. Stick to 325°F (160°C). Too much heat will ruin the custard layer.
- Cool before slicing. The custard needs time to firm up. I like to chill mine for at least 2 hours before cutting neat squares.