Preheat oven to 180˚C.
Place Dr. Oetker Nona Tarts, butter and egg in a mixing bowl. Mix well.
On a floured surface, roll the dough 0.5cm thickness. Cut the dough into shapes with cookie cutter, place on a lined baking tray.
Bake at 180˚C for 12 - 15 minutes or until golden brown.
Melt cooking chocolate in a bowl with microwave oven or by double-boiling.
Fill the sunken part with melted Dr. Oetker Nona Cooking Chocolate and decorate with some sprinkles. Leave to set before serving.