Cut carrots into cubes, mushrooms into slices. Finely chop the parsley, as well as the garlic and onion. Heat the butter in a pan. Add the mushrooms, carrots, garlic, onion and parsley. Fry properly. Then pour the cream and vegetable stock on top. If the sauce is a little thin, dust it with a little flour. Fold in the grated Parmesan cheese. Season with salt and pepper.