Boil the potatoes and
mash them, with a potato-masher or in a mortar, into a smooth paste.
Beat the egg whites with a pinch of salt until they are stiff, then
combine a little at a time the melted butter, sugar, egg yolks, cocoa
powder, the potatoes, milk, the flour passed through a sieve, the
baking powder and almonds. Pour the mixture into a greased baking tin
and cook it in a pre-heated oven at 180°C/350°F for 30 minutes.
When the cooking time is finished, sprinkle over the icing sugar.