Ingredients: 

85g butter at room temperature, plus extra for the tin

60g plain flour, plus extra for the tin

80g chopped dark chocolate – 70% cocoa

5 eggs, separated

Salt

145g caster sugar

15g cornflour

15g cocoa powder

To decorate(optional):

100g sugar

2 tbsp rum or other dark spirits

300g apricot jam

145g dark chocolate, roughly chopped

100g unsalted butter

Instructions:

Heat the oven to 160C (140C fan)/310F. Grease and flour the base of a loose-bottomed 22 cm-diameter tin.

Melt the chocolate in 30-second pulses in the microwave until it melts, then leave it to cool, stirring occasionally to keep it liquid.

Whisk the egg whites with a pinch of salt until foamy, then add 115g sugar. Keep whisking until the mixture is shiny and forms soft.

Beat the butter until soft. Add 30g of sugar and keep beating until fluffy. Add the egg yolks one at a time, ensuring each is well incorporated before adding the next.

Add the melted chocolate and whisk until well combined.

Finally, sift over the dry ingredients, then gently fold in until the mixture is evenly coloured and no pockets of flour remain. Carefully tip the batter into the prepared tin and gently level the top.

Bake for 35-45 minutes until a skewer comes out clean. Let it sit in the tin for 10 minutes.

Meanwhile, make the rum syrup. Combine the sugar and 100ml water and bring to a boil while stirring. Remove from the heat, stir in the rum, leave to cool slightly, brush over the cake, and leave to cool completely.

With a bread knife, cut the cooled cake in half laterally and spread more syrup over the top of the base.

Spread a third of the apricot jam over the base of the cake, replace the top half, and spread the rest of the jam over that and the sides of the cake. Leave to set for a couple of hours. Pour chocolate over the centre of the cake.

Best eaten after a couple of days.