Boil a large pot of water, add ½ tsp salt, and egg noodles. Cook until al dente, by following the instructions on the package. Stir in butter once the noodles are drained.
Cut beef into 1.5 inch long strips, and longer ones, cut in half. If the steak is too thick, pound it down to about ½ inch thickness. Sprinkle with salt and pepper. In a large skillet, heat oil over high heat, and add beef strips. Sear for about 30 seconds on each side, or until browned, transfer to a clean plate; continue cooking the remaining steak, add to cooked steak and set aside.
Turn heat down to medium temperature, add butter, and sauté onions until transparent, the add garlic and mushrooms, stirring occasionally, and cook until tender about 3-4 minutes. Add white wine and boil until reduced to half, and begin scraping the bottom of the skillet for all of the brown bits.
In a separate bowl, whisk together beef broth, flour, Worcestershire sauce, and paprika. Add to the skillet, stirring to combine. Allow to simmer for another 5 minutes, stirring constantly until fully incorporated and sauce begins to thicken. The longer it cooks the thicker the sauce becomes.
Stir in sour cream and incorporate into the sauce until smooth and creamy. Add the beef and any juices from the plate into the skillet. Simmer, for about 5 minutes, season if needed with any extra salt and pepper.
Serve over egg noodles, and garnish with chopped parsley.
