Chop the chocolate and melt 300 g of it with butter in a pot over a warm water bath. Beat the eggs and sugar with the whisk of the hand mixer until thick and creamy. Stir in chocolate butter. Mix flour, cocoa and baking powder. Briefly stir in the flour mixture. Fold in the rest of the chocolate
Cut off the dough with an ice-ball former (approx. 8 cm Ø). Spread on approx. 3 baking trays lined with baking paper. Only fill 2/3 of the ice cream scoop so that the biscuits do not become too large. Or use a smaller ice-cream cone former to place two dough balls on top of each other. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) one after the other for 10-12 minutes. Allow to cool down