Heat the oven to 180ºC. Grease a bundt tin. Beat the eggs with butter and icing sugar, stirring well until light and creamy. Add the potato flour with a pinch of salt gradually. Stir into the mixture the cocoa and baking powder, mixing well until blended. Pour the batter into the prepared bundt tin and bake for 40 minutes, until firm and springy to the touch. Remove from the oven and leave to cool.

For the chocolate glaze: Mix together the warm melted chocolate with the mascarpone and add the milk. You can add 2 tablespoons of brandy instead of milk, if desired. Spread the glaze over the ciambella (cake).