Place 1 paper baking tray in each of the recesses of a muffin baking tray (for 12 pieces)
Mix 50 g flour, cocoa, 50 g sugar, 1 vanillin sugar, 1 pinch of salt and 50 g butter in flakes first with the dough hooks of the hand mixer and then briefly with your hands to form crumbles
Coarsely chop the chocolate coating and nuts. Melt 175 g chopped chocolate coating in a hot water bath. Let cool off
Cream 100 g butter, 100 g sugar, 1 vanillin sugar and 1 pinch of salt. Gradually stir in liquid chocolate coating, then eggs one by one. Mix 150 g flour and baking powder, alternating with the milk and stir in briefly. Fold in chopped nuts and 75 g chopped couverture
Fill the dough into the paper cups. Spread crumbles on top. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/gas: level 2) for approx. 25 minutes. Let them cool down
Melt 50 g chopped chocolate coating in a hot water bath. Pour into a freezer bag, cut off a small corner. Decorate muffins with it in strips. Leave to dry