Step 1

Preheat the oven to 180C / Fan 160C / 350F / Gas Mark Grease and line a 20cm (8-inch) round cake tin and set to one side.

Step 2

Separate the eggs into two separate mixing bowls. In a third bowl, mix the baking powder and almond flour.

Step 3

Beat the egg whites using an electric mixer until you have stiff peaks. Add 1-2 tbsp of caster sugar and beat again until glossy.

Step 4

In a separate bowl add the egg yolks, melted butter, caster sugar and lemon zest. Beat with an electric mixer until pale and fluffy - around 1-2 minutes.

Step 5

Add approx 1-2 tbsp of the egg white mixture to the egg yolks and beat together to loosen the mixture.

Step 6

Pour in a third of the almond flour mix and then add a third of the beaten egg whites to the egg yolk mixture. Use a spatula or metal spoon to gently fold in, ensuring there are no loose lumps of flour.

Step 7

Repeat again with another third of the flour and egg whites, and again until all the mixture is combined. Pour into the lined cake tin and gently smooth the top with a palette knife.

Step 8

Sprinkle over the flaked almonds and then bake for 25-30 minutes until risen and golden brown on top. Leave on a cooling rack to cool before removing from the tin, dusting with icing sugar and serving.