Put the pasta in boiling salted water and cook for ten to twelve minutes. Cut the bacon into cubes and fry until crispy in a pan. Clean, wash and slice the mushrooms.
Peel and finely chop the onion. Fry the mushrooms and diced onion. Deglaze with the cream and let it boil down a little. Season sauce with salt and pepper. Whisk the egg yolks and stir into the no longer boiling sauce.
Wash parsley, dab dry and cut into strips. Drain the spaghetti and arrange in a bowl with the sauce. Sprinkle with parsley and parmesan.