1. Preheat the oven to 190'c.Crease and base-line two 20cm/8in sandwich tins (pans). Melt the chocolate.

2.Cream the butter with the sugar until light and fluffy. Beat in the vanilla, then gradually add the beaten eggs. Stir in the chocolate and yogurt evenly. Fold in the flour with a metal spoon.

3.Divide the mixture or until the cakes are firm to the touch. Turn out and cool on a wire rack.

4.Make the frosting. Melt the chocolate and butter in a pan. Off the heat, Stir in the icing sugar and yogurt. Mix until smooth, Then beat until cool and slightly thickened. Use a third to sandwich the cakes together.

5.Wroking quickly, spread the remainder over the top and sides. Sprinkle with icing sugar and decorate with chocolate curls.