1. Cream the butter and sugar together. Finely chop the marzipan and mix it in. Beat in the egg, then add the flour, cornstarch, extract, and baking powder, and knead to form a smooth dough.
2. Line a baking sheet with parchment paper. Fill a prepared plastic bottle with the dough and pipe strips or mounds onto the baking sheet. Bake in a preheated oven at 180 °C (350 °F) for about 10–12 minutes, or until golden brown. The cookies will become crispy after cooling. Decorate with melted chocolate, if desired.
