Onions peel and cut into slices. Peel carrots and cut into small pieces. Clean, wash and quarter the mushrooms. Fry onions in 20 g fat, add carrots, deglaze with 100 ml water and stew for about 10 minutes.
Turn meat in flour, fry in the remaining fat for 2-3 minutes on each side, season with salt and pepper. Remove the meat from the pan and keep covered and warm. Brown half of the mushrooms in the pan, add stock and cream.
Add remaining mushrooms to the vegetables and cook for 5 minutes. Bring mushroom sauce to the boil, stir in sauce thickener and bring to the boil again. Season sauce with salt and pepper. Chop parsley coarsely, fold into the vegetables and season to taste.
Arrange vegetables and schnitzel on a plate, serve with sauce.