Wash and clean the vegetables. Cut aubergine and zucchini into slices. Cut tomatoes into quarters and peppers into strips. Peel onions and dice 2 roughly. Wash and shake dry oregano and chop the leaves, except for some garnish, from the stems.
Finely dice the remaining onion. Cut olives into slices. Peel garlic and press it through a garlic press. Cut the cheese into 12 equal pieces. Knead minced meat, egg, onion, garlic, olives, breadcrumbs and milk and season with salt and pepper.
Form into 12 meatballs and fill each with 1 piece of cheese. Heat 1 tablespoon of oil in a frying pan and fry the meatballs for approx. 8 minutes, turning them over. Heat 1 tablespoon of oil in a second pan and fry the prepared vegetables for approx. 5 minutes, turning them over.
Stir in tomato paste, pour in stock and season with salt, pepper and sugar. Bring to the boil and braise for about 4 minutes. Arrange vegetables and meatballs. Bread tastes good with it.