Oven-baked Baumkuchen

Grease a 25 × 11 cm loaf tin with 5 g butter and line the base with baking paper. Preheat the oven grill. Keep 1 egg whole and separate the whites and yolks of the other 4 eggs.

Let the butter reserved for the batter soften. Whip the reserved whites to stiff peaks. In another bowl, beat the remaining 200 g softened butter with the sugar, vanilla sugar and salt. Add the reserved whole egg, followed by the yolks and rum. Sift in the flour, cornstarch and baking powder and mix. Gently fold in the whipped whites with a spatula.

Spread a thin layer of batter in the tin. Position the surface about 20 cm below the grill and brown for about 2 minutes, watching closely. Remove with oven gloves, spread another thin layer over the cooked one and repeat until all the batter is used. Lower the rack as the cake grows to keep the same distance from the grill.

Loosen the sides with a knife, turn out onto a rack and remove the paper. Cool for about 60 minutes. Chop the chocolate and melt it with the oil over a water bath, keeping the bowl clear of the water. Coat the cold cake and let the chocolate set for about 30 minutes before slicing.