Meanwhile, heat 1 tablespoon oil in large skillet on medium-high heat. Season steak with 1/4 tsp each salt and pepper, and cook in 2 batches until browned, 1 minute per side; transfer to bowl.
STEP 3
Reduce heat to medium. Add onion and 1 tablespoon oil and cook, stirring occasionally, 6 minutes. Add mushrooms, remaining tablespoon oil, and 1/4 teaspoon each of salt and pepper. Increase heat to medium-high and cook, tossing occasionally, until mushrooms release their juices and begin to brown, about 6 minutes. Stir in garlic and cook for 1 minute.
STEP 4
Add wine and cook, scraping up any browned bits, about 1 minute. Add broth and simmer until slightly reduced, 3 minutes.
STEP 5
Remove from heat and stir in sour cream, mustard, and Worcestershire sauce. Fold beef into sauce and spoon over noodles. Serve sprinkled with parsley.