Stir the flour, cocoa and melted butter in a saucepan. Add the milk, bring to the boil and knead in the grated cooking chocolate with a wooden spoon. Meanwhile, heat the whole mixture until it separates from the saucepan. Remove from the heat and, using a hand mixer, gradually beat in the yolks. Cool.
Whip egg whites with sugar until stiff and mix gently. Butter the ramekins and line with sugar. Pour the mixture almost up to the edge. Pour 1.5 cm of water into the grease tray and place the ramekins in it. Bake at 200 °C for about 12 min with the stove closed.
Open the stove a crack and let the souffle sit for another 12 min. with the stove turned off. Next, remove from the ramekin and serve with vanilla sauce.
Tip: Feel free to use better chocolate – the more delicious the result!