Rinse meat cold, dab dry and cut into strips. Clean mushrooms, rub with kitchen paper and cut in half or quarters depending on size. Peel onions and cut into strips. Cut the gherkins into slices.
Preheat the oven for the Roastital oven (electric oven: 100 °C/circulating air: 75 °C/gas: see manufacturer). Peel and wash the potatoes and grate them roughly in a bowl. Season with salt and pepper. Heat 4 tablespoons of oil in a coated pan.
Fry about 12 small Rösti in each portion. To do this, first lightly squeeze 1-2 tbsp. of the potato mixture between your hands, then press flat and fry for approx. 5 minutes until golden brown, turning once. Drain on kitchen paper and keep warm in the oven.
Heat 2 tablespoons of oil in a large frying pan. Brown the meat in portions at high heat and remove. Heat 1 tablespoon of oil in the pan. Fry the mushrooms in portions. Add the onions and fry.
Deglaze with wine. Stir in sour cream and simmer briefly. Heat meat and gherkins in the sauce. Season to taste with salt and pepper. Serve with roast titbits.