Spiced Orange Sandwich Cookies
Combine the marzipan, powdered sugar, egg white, cocoa powder, cinnamon and chopped orange peel in a large bowl. Knead with the dough hook attachment of an electric mixer until smooth. Shape the dough into a ball, wrap with plastic wrap and refrigerate for about 2 hours.
Roll the dough out onto a surface dusted with powdered sugar until about 3-4 mm (approximately 1/10-1/8 inch) thick.
Use a rectangular cookie cutter with scalloped edges to cut the cookies out and place on a baking sheet lined with parchment paper. Brush the cookies with the beaten egg yolk and sprinkle half with the colorful sprinkles. Bake in an oven preheated to 190° (approximately 375°F) for 12 minutes. Remove from the oven and allow the cookies to cool on the baking sheet.
Spread the orange marmalade onto the cookies without sprinkles and top with the sprinkle-covered cookies. Store in an airtight container.