Step 1

1 Cook the noodles according to package directions; drain and set aside.

Step 2

2 Heat oil in large skillet. Season beef with salt and pepper, add to hot skillet; stir constantly until meat is browned. Add onions and mushrooms; cook until beef is cooked through and onions are tender.

Step 3

3 Stir in flour; cook 1 minute. Slowly stir in beef broth and mustard; bring to a simmer. Add sour cream and stir until evenly mixed.

Step 4

4 Remove from heat and toss with noodles. Garnish with diced green onions, if desired.