Cook the spaghetti in salted water as usual and drain. Briefly fry the onion together with tomato paste and then deglaze with the tomatoes. Add the sour cream and the broth powder.
Bring everything to the boil briefly, add the processed cheese and let it melt. Then season with pepper, salt and oregano and season to taste. To decorate, add the parsley to the finished dish and serve with the spaghetti.