Peel and wash the potatoes, cut them into pieces and boil them up in salted water, cook for about 20 minutes. Add peas to the potatoes 5 minutes before the end of the cooking time. Peel onion and cut into rings. Heat 1 tablespoon of oil in a pan. Fry the onion in it until golden brown and take it out. Heat 1 tablespoon of oil and fry the cutlet in it for about 3 minutes on each side.
Season the cutlet with pepper. Add the onions back to the cutlet and keep warm. Drain the potatoes. Add milk and fat and mash roughly. Season to taste with salt and nutmeg. Arrange pea puree, cutlet and onion rings on a plate and serve garnished with parsley