Mix all other ingredients together to form a dough. Grate 50 g chocolate or cut into small pieces and mix in. Quarter a banana lengthways and cut into very small pieces. Mix these with the dough.
Fill 12 muffin molds about a third full with batter. Place a thin slice of the rest of the banana on the dough. Then place a piece of the remaining 50 g or 12 pieces of chocolate on each of these slices. Then fill the molds with the rest of the batter.
Bake at 175 ° C for about 20 minutes, until the muffins tear open on top and turn a little darker.