Cook the tortellini in boiling salted water for 12-14 minutes. In the meantime peel and finely dice the onion. Heat the oil in a pot and fry the onion until transparent. Add minced meat and fry briefly.
Season with salt and pepper. Add cream, milk and stock, bring to the boil and simmer for about 10 minutes. Add peas to the sauce about 2 minutes before the end of the cooking time. Roughly dice the cheese and melt in the sauce.
Drain the tortellini and serve with the sauce in deep plates. Garnish with parsley as desired.