Preheat oven to 160 °C (325F). Grease a 9in spring form cake tin and line the bottom with greaseproof paper.

Cream the butter then add 1/3c sugar slowly, beating in between additions. Add the egg yolks one at a time, beating in between. Melt the chocolate and add it to the mixture along with the almond essence and hazelnuts. Beat. Fold in the cocoa and flour.

Whisk the egg whites until stiff, then add 1/3c sugar slowly, whisking in between additions. Stir about a quarter of this into the cake mixture to lighten it, then *fold* in the remainder. Spoon this into the cake tin.

Bake for 60 - 70 minutes, until the top is firm and the centre cooked (test with a metal skewer). Cool and remove from tin.

Warm the apricot jam until it is semi liquid. Spread over the top and sides of the cake. Allow to cool and set slightly. Melt the butter and the chocolate for the icing and mix with the brandy, if used. Cool until it reaches a consistency for icing, then ice the top and sides of the cake.