Cut butter into pieces. Grate marzipan. First knead flour, butter, sugar, marzipan, orange peel, spice and egg with the dough hooks of the hand mixer, then work into a smooth dough with your hands. Wrap the dough in foil and chill for about 30 minutes. Roll out dough on a floured work surface 3-4 mm thin and cut out hearts in 2 sizes (4 and 5.5 cm high).
Line 2-3 baking trays with baking paper and place the hearts on top. Knead the dough again, roll out again and cut out the hearts. Bake the cookies sheet by sheet in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 8 minutes. Let them cool down. Stir icing sugar and orange juice until smooth and thick. Cut the icing in half. Colour one half light red with red and yellow food colouring. Pour some white and red icing into one freezer bag each, cut off a small corner. Coat the hearts with the remaining icing.
Cut the icing in half. Colour one half light red with red and yellow food colouring. Pour some white and red icing into one freezer bag each, cut off a small corner. Coat the hearts with the remaining icing. Decorate red hearts with white dots, some white hearts with red edges. Let the cookies dry
Waiting time approx. 1 hour