01 - Season the beef strips with salt and black pepper, then toss with all-purpose flour to coat evenly.
02 - Heat 1 tbsp butter and olive oil in a large skillet over medium-high heat. Add the beef in batches and sear quickly, about 1-2 minutes per side, until browned. Remove beef and set aside.
03 - Add the remaining 1 tbsp butter to the skillet. Sauté the chopped onions for 3 minutes until translucent. Add mushrooms and cook until softened and golden, about 5-7 minutes.
04 - Stir in minced garlic and tomato paste; cook for 1 minute to incorporate flavors.
05 - Pour in beef broth, scraping up browned bits from the skillet. Bring to a simmer and cook 3-4 minutes to reduce slightly.
06 - Lower heat and stir in sour cream, Dijon mustard, and Worcestershire sauce until smooth. Return beef and any released juices to skillet and gently simmer for 2-3 minutes to heat through without boiling. Adjust seasoning with salt and pepper.
07 - Prepare egg noodles according to package directions, then drain thoroughly.
08 - Plate the beef stroganoff over noodles and garnish with chopped fresh parsley.