Beat the butter and sugar until frothy. Add egg yolks one at a time. Stir in the salt, rum and milk. Mix flour with baking powder, gingerbread spice and cocoa powder and add to the butter, sugar and egg mixture. Beat the egg whites until stiff and fold into the batter. Place the dough on a greased baking sheet and bake at 200 ° C for about 20 minutes. After cooling, decorate with chocolate icing and, if desired, with colorful sprinkles.
Tip: If you are expecting a lot of guests, you can easily prepare twice the amount of dough. The cake is successful and tastes wonderful.