Clean, wash and cut the peppers into large pieces. Peel onion and garlic. Chop the onion finely, press the garlic through a garlic press. Heat oil in a pan and fry the peppers for 2-3 minutes. Add onions and garlic, fry briefly and season with salt, pepper and oregano. Add the chopped tomatoes and stock, bring to the boil and simmer for 4-5 minutes.
In the meantime, put tortelloni in plenty of boiling salted water and cook for about 1 minute. Pour onto a sieve and drain well. Season the sauce again with salt and pepper and mix with the tortelloni. Put it in a greased, ovenproof dish and sprinkle with crumbled feta cheese and parmesan. Bake in the preheated oven (electric cooker: 200 °C/ gas: level 3) for about 20 minutes. Serve garnished with fresh oregano