Separate the egg whites from the yolks.
The milk chocolate is crushed / cut into small pieces and is thus prepared for incorporation into muffins.
Put the muffin tins in the special tray.
Mix the butter with the sugar and a tablespoon of cocoa. Add the yolks one by one, one at a time.
Beat the egg whites / mix well with the vanilla and incorporate, little by little, in the composition with the yolks. Add, according to taste, the essence of almonds, or rum, after which the flour is incorporated, taking care not to form lumps.
Put a spoonful of the composition in the muffin tins, sprinkle the chocolate pieces in them and cover with another spoonful of the composition. They can be decorated with ornaments and put in the oven over low heat. When they are ready, remove the muffins, leave to cool slightly and decorate with white chocolate, melted in a bain-marie with a tablespoon of oil, over which sprinkles ornaments.
The composition is enough for 12 muffins.