For the minced meat, chop the onion and soak the bread slices. Mix the minced meat with the egg, onion and bread and season with salt and pepper. Shape the mixture into 10 balls while pressing in a piece of feta cheese. Sear the balls and put them in a baking dish.
Preheat the oven to 200 °.
For the sauce, chop and sauté the small onion, dust with flour and deglaze with 200 ml of water. Add tomato paste, instant stock, cream, Tabsaco, Maggi, sugar and season with salt and pepper.
Pour the sauce over the balls and sprinkle with the crumbled feta cheese.