Prepare a smooth mixture of 4/5 cup (200 g) of sugar, eggs and cocoa. Add the melted butter, grated apples, baking powder and flour. Put the resulting dough into a greased oven dish, which you've sprinkled with flour.
Bake on the lower element only at first, then on the top one as well, until the edges unstick from the form. Top the finished cake with the prepared topping.
The topping is prepared from 2/5 cup (100 g) of powdered sugar, a little rum and the juice of 1 lemon. Stir until you get a smooth mixture.