Stollen with Marzipan Poppy Seed Filling
Beat butter until creamy using an electric hand mixer. Gradually beat sugar, eggs, salt and quark into butter. Mix flour and baking powder and knead into butter mixture to a smooth dough using a stand mixer fitted with a dough hook.
For the filling, mix poppy seeds and water. Cut marzipan into small pieces and mix with egg white, poppy seed mixture and raisins. Place filling in a pastry bag without a tip.
Press dough between sheets of parchment paper into an oval about 30 cm long (approximately 12 inches long). Pipe filling onto dough in two lengthwise strips. Fold long sides of dough over filling towards the center and squeeze. Place stollen seam-side down in a greased loaf pan. Place loaf pan upside-down on a baking sheet lined with parchment paper.
Bake stollen in oven preheated to 200°C (fan: 180°C, gas mark 3-4)(approximately 400°F) for 40-45 minutes. Remove loaf pan from stollen and bake stollen 10-15 minutes more. Let stollen cool and dust with powdered sugar to serve.