In a large Dutch oven heat the oil over high heat and brown the cubed stew meat. 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 stew meat to the pan.
Stir in seasoning salt, Worcestershire sauce and beef broth. Bring to a boil, then cover and reduce the heat to medium. Simmer for 1 to 1 1/2 hours or until meat is fork tender.
Bring a large pot of lightly salted water to a boil. Add the egg noodles and cook for 8 to 10 minutes or until al dente; drain.
In a skillet, 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 cornstarch and the water, and stir into the meat mixture; stirring constantly. Stir in sour cream until creamy serve over the egg noodles.