Pre heat the oven to 180 C / 350 F. Grease and line a 20 to 23 cm / 9 or 10 inch cake tin.

Put the chocolate, butter, coffee and vanilla into a saucepan and melt on low until combined. Cool to luke warm.

Put the egg yolks and sugar into a bowl and beat until light and creamy, gradually add the chocolate mixture. Fold through the ground almonds.

Using clean beaters and bowl beat the whites until soft peaks form , add extra sugar and beat well

Fold the whites through the chocolate mixture

Bake 40-45 minutes. Test with a skewer , to make sure it comes out clean

This can be simply sprinkled with icing sugar or make a chocolate ganache to go on top.