Cut the steak into 1/2" thick strips.
Season the strips with salt and pepper.
Add 2 tablespoons of the flour to a plastic bag for dredging the strips.
Toss meat in the and shake to coat.
In a dutch oven, heat olive oil over medium high heat.
Cook strips in small batches until lightly browned on both sides (about 3 minutes per batch).
Transfer to cooked meat to a plate and set aside.
Add butter and onion to the pan. Reduce heat to medium and cook until translucent (about 4 minutes).
Add mushrooms and garlic, and cook until softened (about 4 minutes).
Sprinkle remaining flour over mushrooms. Stir and cook for 2 minutes,
Add the Worcestershire sauce, mustard and beef broth and bring to a boil.
Reduce heat and simmer uncovered for 5 minutes.
Add the beef back to the pot and cook for an additional 4 minutes.
Serve over egg noodles.