Wash the schnitzel, dab dry and cut into strips. Heat oil in a large pan and fry the meat strips on all sides over a high heat. Fry the meat at medium heat for another 4-5 minutes. Season with salt and pepper. Stir in mustard.
Add stock little by little. Stir in sour cream and simmer for two minutes. In the meantime clean and wash the spring onions. Cut spring onions and gherkins diagonally into slices. Add both to the meat and cook briefly. Season to taste with salt and pepper and fill into an ovenproof dish. Wash parsley and chop finely. Peel and finely grate the potatoes. Mix the grated potatoes, parsley and egg yolk. Season with salt and pepper.
Season to taste with salt and pepper and fill into an ovenproof dish. Wash parsley and chop finely. Peel and finely grate the potatoes. Mix the grated potatoes, parsley and egg yolk. Season with salt and pepper. Spread on the Stroganoff and bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 45 minutes. Serve garnished with parsley
Waiting time approx. 40 minutes