This is based on the famous Viennese Sachertorte
150g plain chocolate, melted and cooling.
6 eggs, separated.
100g castor sugar.
Half teaspoon vanilla extract.
55g plain flour.
100g ground almonds.
1 heaped tablespoon cocoa powder.
Whisk the egg whites to soft peak stage.
Cream the butter and sugar until light and fluffy.
Whisk in the chocolate and vanilla. Followed by the egg yolks (one at a time) on full speed.
Fold in the flour, ground almonds and cocoa powder.
Fold in one third of the egg whites and then the remainder, gently.
Pour in to 23cm tin (buttered and base lined with parchment paper) in one go and level gently.
Cook in pre-heated oven at 180C or Gas 4 for 45-50 minutes.
To finish the cooled cake (optional), brush with warmed apricot jam and cover with a chocolate icing made of 200ml double cream heated and poured over at least 115g plain chocolate -cool before covering cake.
I made two smaller cakes and cooked for about 20 minutes by when the internal temperature had reached over 95C. The finished cake keeps well and retains its moistness for at least a week – there was only this scrap left by then