Bring 3-4 l salted water (1 teaspoon salt per litre) to the boil. Clean, wash and cut leek into rings. Clean mushrooms, wash if necessary and cut into slices. Grate cheese finely.
Cook the pasta in boiling salted water according to the instructions on the packet. Heat the oil in a large pan. Fry the bacon in it. Fry mushrooms and leek for about 4 minutes.
Mix eggs, cream and 2⁄3 parmesan. Season with salt and pepper. Drain the pasta. Mix immediately with egg cream and mushroom mix. Serve with the rest of the cheese.