Mix apples with rum and vanilla sugar; set aside for 1 hour.
Preheat oven to 180 C / Gas 4. Grease a round springform cake tin.
Cream together butter and sugar. Gradually beat in eggs, one at a time, beating well after each addition.
Mix in nuts, cocoa and cinnamon. Mix flour with baking powder and fold into the mixture one tablespoon at a time. Lastly, fold in apples.
Pour batter in prepared tin and bake in preheated oven for about 60 minutes. Cool on a wire rack.
For the icing: Mix sugar with rum, enough lemon juice and 1-2 tablespoons lukewarm water to make a thin glaze. Brush onto cooled cake and sprinkle with flaked almonds.
