01 - Season beef strips with salt and pepper, then toss with flour until evenly coated.
02 - Heat 1 tablespoon butter and olive oil in a large skillet over medium-high heat. Brown the beef in batches for 1 to 2 minutes per side, removing it before fully cooked. Set aside.
03 - In the same skillet, add remaining butter. Sauté onions for 2 to 3 minutes until softened, then add garlic and cook for 30 seconds.
04 - Add mushrooms to skillet and cook for 5 to 7 minutes until they release moisture and turn golden.
05 - Pour in white wine if using, scraping the browned bits from the pan. Simmer for 2 minutes.
06 - Stir in beef broth and Worcestershire sauce, then reduce heat and simmer for 3 to 4 minutes to slightly thicken.
07 - Lower heat and stir in sour cream and Dijon mustard until smooth. Avoid boiling to prevent curdling.
08 - Return beef along with any juices to pan. Simmer gently for 2 to 3 minutes until beef is cooked through and sauce is creamy. Stir in chopped parsley.
09 - Cook egg noodles according to package instructions. Drain and toss with remaining butter.
10 - Serve beef stroganoff over buttered egg noodles and garnish with extra chopped parsley.