Clean the leek and mushrooms. Cut the leek into slices, leave the mushrooms whole or halve depending on the size (you can also use canned mushrooms).
Heat the oil in a pan and fry the minced meat until it crumbles while stirring. Add the leek and mushrooms and fry them too. Deglaze with vegetable stock and cream. Bring to the boil and thicken with a sauce thickener. Season with salt, pepper and paprika. Finally stir the parmesan into the sauce and season to taste again.