In the meantime, peel and finely chop the onion and garlic. Fry the minced meat in heated olive oil until crumbly, seasoning a little with salt and pepper. Add the onions and garlic and fry for about 5 minutes. Then deglaze the whole thing with the beef stock and bring to the boil. Stir in the tomato paste, then add the sour cream. Season to taste again and, if necessary, thicken with a sauce thickener.
Drain the spaghetti, arrange on plates and pour the sauce over them. Serve immediately.
Tip: Finally, I add fresh, chopped parsley over the top.