Finely dice the onion. Fry the minced meat with the onion in the butter. Skin and finely chop 2 tomatoes. Also add to the minced meat mixture and season with salt and pepper.
Boil the pasta and drain. Mix the yogurt with the garlic and mix with the pasta.
Season the minced meat mixture again with salt and parsley and pour over the pasta. Cut the remaining two tomatoes into cubes and serve as a garnish on the dish.