Mix the flour with baking powder and pudding powder.
In a separate key, stir the eggs with the buttermilk, lemon peel, sugar, vanilla sugar and butter vigorously. Add to the flour mixture and stir quickly. Small lumps are allowed to develop. Finally mix in the chocolate cubes.
Pour the dough into the wells of the muffin pan and bake at 180 ° C for 20-25 minutes.