Peel and chop the onion. Heat 1 tablespoon of oil, fry the diced onion until transparent. Add tomatoes while stirring, bring to the boil and season with salt, pepper and sugar. Wash the marjoram, shake dry and, except for a little garnish, pluck leaves from the stalks and stir into the sauce.
Let the sauce simmer. Wash the meat, dab dry and season with salt and pepper. Mix breadcrumbs and cheese. Whisk eggs in a deep dish. Turn meat one after the other in 4 tablespoons of flour, egg and breadcrumbs.
Prepare spaghetti in boiling salted water according to package instructions. Heat 4 tablespoons of oil in a frying pan. Fry escalopes in portions in hot oil while turning. Drain the noodles in a sieve and put them back into the pot.
Fold in the sauce. Arrange schnitzel and noodles on plates and garnish with marjoram.