Preheat oven to 180øC/350øF/gas mark 4.

Melt the chocolate over a pan of simmering water. Set aside to cool. Whisk the eggs with the caster sugar for 5 minutes, until they have increased in size by four, and are pale and thick. Add the melted chococate, making sure it's not too hot, or the mixture will harden. You could put 1 tbsp of any type of liqueur you like in at this point, if you wish.

Turn out into a grease proof lined loose bottomed cake tin (7 inches approx) and bake for 50 minutes, or until a knife inserted in the centre comes out clean. Cool in tin and turn out.

To serve, dust with cocoa and choose one of the two recipes following: