Mash the bananas with a fork and grate the chocolate finely.
Mix the flour, baking powder, cinnamon, baking soda and cocoa in a bowl. Beat the egg with the sugar until frothy, then add the milk and oil and mix, then add the hazelnuts. Mix in the flour mixture with the spatula and finally mix in the mashed bananas and grated chocolate.
Pour the dough into 12 greased muffin cups and bake at 180 ° for about 25 minutes.
Tip:
Glaze the muffins with a frosting mixture. To do this, mix powdered sugar, water and lemon juice until a thick mixture is formed and spread it over the muffins.