Grease a fat pan (approx. 32 x 39 cm; approx. 3.5 cm deep) and dust with flour. Warm 75 ml milk and 1 tbsp. sugar lukewarm. Crumble yeast into it and dissolve it. Pour 375 g flour into a bowl, press a depression in the middle.
Pour the yeast milk into the bowl and mix it with some of the flour to make the pre-dough. Cover and leave to rise in a warm place for about 15 minutes.
Add 75 g soft butter, the egg, 5 tablespoons of milk (room temperature), 50 g sugar, 1 packet of vanilla sugar and 1 pinch of salt to the pre-dough and knead everything smooth with a hand mixer. Cover and leave to rise for 30-40 minutes.
Melt 225 g butter at low heat. Mix 300-325 g flour, cocoa, 150 g sugar, 1 packet of vanilla sugar and 1 pinch of salt. Add the liquid butter, kneading everything into crumbles first with a hand mixer and then briefly with your hands.
Coarsely chop the almonds and nuts. Dust the yeast dough with a little flour and roll out on the fat pan. Leave to rise for 20-30 minutes.
Bring 150 g butter, 200 g sugar and 1 packet of vanilla sugar to the boil. First fold in almonds and nuts, then stir in approx. 5 tablespoons of milk. Let cool down for about 10 minutes.
Carefully spread the lukewarm nut mixture on the yeast dough. Sprinkle with sprinkles and grate them between your fingers. Bake in the preheated oven (electric cooker: 200 °C/circulating air: 175 °C/gas: level 3) for approx. 20 minutes.
Cut the cake into squares (approx. 8 x 8 cm) and halve diagonally. Coarsely chop the couverture separately and melt in a hot water bath. Fill each into a freezer bag and cut off a small corner at the bottom.
Decorate half of the triangles with darker, the rest with white couverture in strips. Leave to dry.