Wash the potatoes and cook for 15 minutes. Drain, let cool briefly and peel. Roughly grate the potatoes. Mix with egg and starch, season with salt and pepper. Melt 30 g butter and mix with milk.
Heat 10 g butter and 1 tablespoon of oil in a frying pan (24 cm Ø). Press the grated potatoes in it to a flat cake. Sprinkle with approx. 1/2 milk-butter mixture, cover and roast over medium heat for approx. 5 minutes.
Turn the Rösti over, sprinkle with the rest of the milk-butter mixture and roast for a further 5 minutes in a closed pan. Keep Rösti covered and warm. In the meantime, clean, wash and roughly dice the peppers. Peel onions, cut 2 onions into wedges.
Dab the meat dry and cut into approx. 12 large cubes. Season meat, paprika and onion slices with salt, pepper and paprika powder, drizzle with 4 tablespoons of oil and mix.
Heat the fat pan of the oven in the preheated oven (electric oven: 225 °C/ circulating air: 200 °C/ gas: see manufacturer) for approx. 5 minutes. Spread the vegetable-meat mixture on the hot tray and braise in the preheated oven at the same temperature for 10-15 minutes.
Wash and clean the mushrooms and dab them dry well. Wash parsley, shake dry, pluck leaves from the stalks and chop finely. Chop the remaining onion finely. Cut the bacon into strips and leave them crisp in a pan without fat.
Add onions and mushrooms and fry for about 5 minutes while turning. Deglaze with cream, bring to the boil and season with salt and pepper. Cut Rösti into cake pieces. Arrange meat, Rösti and mushrooms on plates.
Sprinkle with parsley. Add the remaining pieces of toast.