Peel onion and garlic. Chop the onion finely, press the garlic through a garlic press. Coarsely chop the olives, except for a few for garnishing. Heat the oil in a pan, crumble the minced meat into it and fry it thoroughly. Finally add onions and garlic and fry briefly. Then add chopped olives, tomato sauce and stock and season with salt, pepper and oregano.
Simmer the sauce in an open pot for 5-10 minutes. Meanwhile cook spaghetti in plenty of boiling salted water for about 10 minutes. Coarsely grate the feta cheese. Pour the finished spaghetti onto a sieve and drain. Mix spaghetti with minced olive sauce and spread on plates. Sprinkle with feta cheese and remaining olives and serve garnished with fresh oregano as desired