Method

Cake

Preheat the oven to 180 ºC.

Line a 22×22 cm square cake tin with baking paper.
Place the eggs and castor sugar into the bowl of a cake mixer and beat until the mixture thickens and becomes very pale in colour, about 6 minutes. Add the vanilla extract.

Sift the flour over the egg mixture and fold it in with a rubber spatula. Be careful not to knock the air out. Pour the batter into the prepared tin and bake until a skewer inserted in the centre comes out clean, about 15 minutes. Cool the cake on a rack.

Syrup
Put the sugar, water and lemon rind into a saucepan, and bring to a boil. Boil the mixture for about 7 minutes.

Lemon Pastry Cream
Pour 400 ml of the milk into a saucepan, add the lemon rind and just before it boils remove from the heat.

Break the eggs into a bowl and beat well.

Place a sieve over the egg mix and pour the warm milk into the eggs stirring all the time. (using a sieve will remove any stringy bits).

Mix the castor sugar, vanilla extract and corn starch into the remaining milk and stir in well, ensuring that there are no lumps. Pour this mixture into the warm milk and egg mixture and stir using a whisk.

Return the saucepan to the stove and cook for 3-4 minutes until thickened. As soon the mixture has thickened, turn off the heat and continue to stir so that no lumps form. Place in a plastic container and cover with plastic wrap to prevent a film from forming.

Allow it to cool for 20 minutes.

Marzipan
Place the ground almonds, icing sugar, egg white and almond essence in the bowl of a food processor and whizz until it comes together, adding a little water if necessary. Form into a ball and wrap in cling wrap until ready for use.

 Assembling the Cake
Once the cake is cooled cut it down the centre into 2 equal rectangular halves. Then split the rectangles in half horizontally to form 4 equal layers.

Soak the cake layers in the warm syrup. Place one piece on a flat surface, layer with 1/3 of the warm custard (it is easier to spread when it is warm), place a layer of cake on top and repeat the process ending with a layer of cake.

Spread the outside of the cake with a very thin layer of smooth apricot jam, this acts as the glue for the marzipan. Roll the marzipan out on a flat surface to about 5 mm thick and carefully place it over the cake. Trim the edges.

Dust with icing sugar and toast the top of the cake with a blow torch. Serve cold.