Preheat oven to 160C (325F). Grease a 23cm (9inch) round baking tin.

Mix the sugar, orange rind and vanilla essence with the melted butter until creamy. Add the egg yolks one at a time. Sift the flour and baking powder and fold into the egg and butter cream. Beat the egg whites with a pinch of salt until firm and fold delicately into the mixture.

Pour into the prepared tin. Bale for 45 minutes or until a skewer or toothpick inserted comes out clean. Leave to cool.

To make the topping, break the chooclate into pieces and place in a mixing bowl. Bring the cream to the boil and pour over the chocolate. stir well until the chocolate is fully melted and the mixture is creamy. Add the orange rind and leave to cool. Prepare the chocolate filling.

CHOCOLATE FILLING
Break 175g dark chocolate into pieces and place in a saucepan with 125g unsalted butter. Heat gently, stirring until melted and well combined. Beat in 75g white sugar and mix well. Add 3 egg yolks and 150g creme fraiche(thickened cream). Beat 3 egg whites with a pinch of salt until firm and fold into the chocolate mixture.

Cut the cake into two layers and place the bottom layer on a serving dish. Spread with the orange marmalade, cover with the chocolate filling and sandwich with the other cake layer.

Cut the orange into slices. Cover the cake with the chocolate and orange topping and decorate with halved orange slices. Refrigerate before serving.

This recipe is an extract from Christelle Le Ru's book SIMPLY IRRESISTABLE FRENCH DESSERTS