Wash the potatoes thoroughly and cook them with their skins in boiling water for about 20 minutes. Drain, rinse with cold water and let it evaporate a little. Peel and press them through a potato press while still hot. Add wholemeal flour, 150 g wheat flour (type 550), salt and 25 g butter.
Warm the milk and 100 ml of water lukewarm, crumble the yeast and dissolve in it. Add to the potato dough and knead to a smooth dough. Peel, quarter, core and roughly grate the apple. Knead 80 g pumpkin seeds evenly into the dough, if necessary add a little more flour.
Cover the dough and leave to rise for 1 hour.
Grease the box mould well. Shape the dough into an oblong loaf and add it, cover and let it rise for another 30 minutes. Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). Brush bread surface thinly with water, sprinkle with remaining pumpkin seeds (20 g) and bake for about 1 hour.