Slice the beef across the grain into thin strips. Salt and pepper the beef to taste.
Melt 2 Tablespoons of the butter in a large skillet over medium-high heat.
Sear the beef strips until browned on all sides. Remove from pan to a plate and set aside.
Melt the remaining 2 Tablespoons of butter in the same skillet.
Cook the mushrooms, onions, and garlic until tender.
Sprinkle the flour over the cooked vegetables in the skillet and stir for one minute.
Turn the heat to low and whisk in the beef broth slowly.
Allow the broth mixture to come to a simmer and thicken.
Once the mixture has thickened, stir in the Worcestershire sauce, dijon mustard, paprika, and sour cream.
Stir in the reserved strips of beef and simmer over low heat for 10 minutes.
Serve over hot cooked egg noodles.