Roast the almonds in a pan without fat. Deglaze with orange juice and let it cool down. Finely chop the apricots.
Mix quark, egg and sugar, stir in almonds with juice and apricots. Mix baking powder and 225 g flour, sieve over the quark mixture. First mix a little with a dough scraper, then knead briefly with your hands on a lightly floured work surface to form a smooth dough.
Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). Cut dough into thirds. Press each piece of dough with your hands to a flat cake (approx. 18 cm Ø). Place 1 marzipan loaf in the middle of each.
Whip one edge of the dough lengthwise over the bread, fold over the other edge and roll slightly inwards (see picture). Shape into a stollen. Press the dough together on the narrow sides. Line a baking tray with baking paper and place the stollen on top.
Brush with about 3 tablespoons of water. Bake in a hot oven for 25-30 minutes.
Melt the butter and brush the still warm stollen with it. Let it cool down and dust it thickly with icing sugar. Wrapped in aluminium foil, the stollen will keep for about 1 week.