Peel and chop onion. Trim and small dice celery. Mince garlic. Trim and slice mushrooms. Set vegetables aside.
Melt 2-tablespoons butter over medium to medium high heat in a Dutch oven or large soup pot. Place steak in Dutch oven and sear both sides (about 3-4 minutes per side). Remove steak and set aside to cool while sauteing vegetables. When cool, slice steak into bite-size pieces.
Add remaining 2-tablespoons butter to Dutch oven and melt. Add onion, celery, garlic, mushrooms and paprika. Saute until moisture is absorbed and vegetables are beginning to appear translucent and golden brown. Stir flour into vegetables and continue to cook 1-2 minutes longer. Stir in 4-cups broth, loosening up brown bits on the bottom of the pan as you stir; add Worcestershire sauce, bouillon, and steak;bring soup to a boil, cover and reduce heat; simmer until meat and vegetables are tender (add additional broth if needed). Add remaining 4-cups broth, bring to a boil, add noodles and cook 8-12 minutes or until noodles are tender. Season to taste with salt and pepper. Serve with sour cream. Sour cream or heavy cream may be stirred into the soup or dolloped on top. Garnish with snipped fresh parsley.