Preheat the oven to 180 ° C top / bottom heat. Line a mini muffin tin with paper liners.
Melt the chocolate and add the butter until it has melted too. Allow to cool slightly.
Mix the butter and chocolate mixture with the egg. Mix the flour with baking powder, baking cocoa, salt and sugar and sift over the chocolate mixture. Stir in carefully, adding the milk and stirring in. Spread the dough in the molds and bake for about 10 minutes. Make a chopstick test. Then let it cool down.