In a large Dutch oven, heat the oil over high heat and brown the diced steak. Remove from pan. In the same pan, saute the bacon, onion and celery until onions are translucent and bacon is fully cooked. Return the browned steak to the pan.
Stir in chicken salt, Worcestershire sauce and beef stock. Bring to a boil then cover and reduce the heat to medium. Simmer for 1 to 1 1/2 hours or until meat is tender.
Bring a large pot of lightly salted water to a boil. Add the egg pasta and cook for 8 to 10 minutes or until al dente; drain.
In a frypan, melt the butter over medium heat and saute the mushrooms for 3 to 4 minutes. Add the mushrooms to the meat mixture.
Bring the meat mixture to a boil. Mix together the cornflour and the water then stir into the meat mixture; stirring constantly. Stir in sour cream until creamy and serve over the egg pasta.