In a medium bowl mix together 2 tablespoons flour, 1/4 teaspoon of salt, and ground pepper. Toss the beef in the flour.
Heat 1 tablespoon olive oil in a large pan over medium heat. Add meat and cook until browned on both sides, about 2-3 minutes each. Remove meat from pan and set aside.
Deglaze the pan with a tablespoon or so of beef broth then heat 1 tablespoon of olive oil and add onions and garlic. Cook until softened, 5-7 minutes. Set onions and garlic aside.
Deglaze pan again with a little beef broth then add mushrooms, cook until softened, 5-7 minutes. Season with salt and pepper.
In a small bowl whisk together beef broth, Worcestershire sauce, and 2 tablespoons flour.
Add beef broth in with the mushrooms and cook until it is slightly reduced, about 5 - 7 minutes.
Stir in cooked beef, onions, garlic, and dijon mustard. Cook until warmed through, 2-3 minutes.
Remove from heat and stir in sour cream. Taste for salt and pepper.
Serve over hot pasta.