Grease 6 ovenproof moulds (each containing approx. 150 ml) and sprinkle with sugar. Chop the chocolate and melt it with butter at low heat, let it cool down. Beat the eggs, egg yolks and sugar with the whisk of the hand mixer for about 5 minutes until creamy.
First sift flour over it and fold in. Then fold in the chocolate. Spread the mixture into the moulds, filling each to approx. 3/4 and placing them on the grid of the oven. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 15 minutes.
Remove the cakes from the oven and turn them over onto dessert plates. They should be baked on the outside, but still be liquid in the centre. Sprinkle with gold leaf and serve immediately. Tip: As a cooking test, after 10 minutes baking time, prick the middle of the cakes with a sharp knife. If the dough is thick, remove the chocolate cakes from the oven.