Peel the onion and cut into strips. Clean, wash and cut the bell peppers into strips. Heat the oil. Sauté onion and bell pepper for about 4 minutes. Add sauce, bring to the boil and season with salt and pepper.
Set aside in a closed pot. Spread the potato balls in one layer on a baking tray lined with baking paper. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 18-22 minutes.
Wash marjoram, shake dry, except for something to garnish, pluck leaves from the stalks and chop. Mix tomato paste, pepper sauce and marjoram and season with salt. Wash the meat, dab dry and spread a thin layer of tomato puree on top.
Whisk the eggs in a deep dish. Turn escalopes one after the other first in flour, then in egg and breadcrumbs. Heat the fat in a large pan. Fry the escalopes in portions for approx. 8 minutes while turning until crispy brown.
Keep ready cutlets warm. Arrange schnitzel, sauce and potato balls on plates. Garnish with marjoram.