Sieve the flour into a large bowl and press a depression into it. Heat 100 ml milk, crumble yeast into it and dissolve while stirring. Stir in 10 g sugar. Pour into the flour bowl and mix with a little flour from the edge to the pre-dough.
Cover and leave to rise in a warm place for about 30 minutes. Warm 300 ml of milk lukewarm. Add 115 g sugar, milk, 300 g butter, eggs, rum and salt to the pre-dough. Knead vigorously with the dough hook of the hand mixer.
Cover and leave to rise in a warm place for about 1 hour.
In the meantime, roughly chop the nuts. Knead the dough again well and cut in half. Roll out each piece of dough on a floured work surface to form an oblong, oval flat cake. Halve the marzipan and roll out each half thinly (approx. 2 mm).
Cover one pancake with each. Spread poppy seed mixture on top, spread about 3/4 of the nuts on top. Roll the long sides of the dough patties inwards on both sides and press lightly. Place each on a baking tray lined with baking paper.
Let it go again for about 20 minutes.
Bake the stollen one after the other in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for approx. 12 minutes. Then turn the oven down (electric oven: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) and bake for another 30-40 minutes.
After approx. 20 minutes cover with foil if necessary. (In the meantime, keep the remaining stollen in a cool place). Remove the stollen from the oven. Melt 75 g butter and immediately spread approx. 1/3 of the stollen, dust with 50 g icing sugar.
Repeat the process until the melted butter and approx. 1/2 icing sugar is used up. Do the same with the second stollen, 75 g butter and remaining icing sugar.