Bring plenty of salt water to the boil in a large pot. In the meantime peel and chop the onions and garlic. Wash and halve the mushrooms. Cook the noodles in boiling salted water according to the instructions on the packet.
For the ragout, wash the steak and dab dry. Dice steak and bacon very finely. Heat the oil in a large pan. Brown the steak and bacon cubes in it thoroughly. Add onions, garlic and mushrooms and fry for approx. 3 minutes. Season with salt and pepper. Dust everything with flour and sauté briefly. Stir in about 400 ml water and sour cream, bring to the boil and simmer for about 3 minutes. Grate parmesan.
Drain the pasta, let it drain and mix with the steak ragout. Season to taste with salt and pepper. Sprinkle with parmesan and stir in.