6 oz. (1 1/2 c.) self-rising flour
6 oz. (2/3 c.) caster sugar
2 oz. plain chocolate, melted or 4 level tbsp. cocoa
1/2 tsp. salt
3 oz. (1/3 c.) cooked mashed potato
4 oz. (1/2 c.) butter
4 tbsp. milk
2 eggs

Cream the butter and sugar with the potatoes. Add the melted chocolate or cocoa. Add eggs alternately with the flour and salt. Pour in milk, mixing well, to make a soft dropping consistency. Divide mixture in half and put in 2 greased 8 inch sandwich tins.

Cook in a moderate oven (400 degrees electric; gas regulo 6) for 25 to 30 minutes. The top will be firm and springy to the touch when it is cooked. Let the cakes cool for a few minutes, then turn out on a wire rack. The 2 sides are sandwiched together with whipped cream or chocolate icing.