You will need 2 x 21cm diameter cake tins greased and lined.
Method
Make up the black coffee. While it is still hot, add the chocolate powder and stir together.
In a large mixing bowl cream the butter and sugar together. Add the beaten egg, one at a time, together with a tablespoon of the flour and beat until well mixed.
Sift the flour and bicarbonate of soda. Fold some of the flour into the cake mixture, followed by some of the yogurt and finally some of the coffee. Alternate folding in the flour, yoghurt and coffee until it is all evenly mixed in.
Spoon into the cake tins and bake at 170 deg C (150 deg C for fan ovens), Gas Mark 4, for 25 minutes, until the cake is firm to the touch.
Turn out and allow to completely cool, before decorating with the chocolate frosting.
