01 - Bring a large pot of salted water to a boil. Cook egg noodles according to package directions. Drain, then toss with a little butter to prevent sticking. Set aside.
02 - Sprinkle the beef strips evenly with salt and black pepper.
03 - Heat 1 tablespoon butter and 1 tablespoon olive oil in a large skillet over medium-high heat. Add beef in batches and sear quickly until browned, about 1 minute per side. Remove beef and set aside.
04 - Add remaining butter and olive oil to the skillet. Sauté onions until softened, about 2 to 3 minutes. Add mushrooms and cook until tender and browned, approximately 5 minutes. Stir in garlic and cook for 1 more minute.
05 - Sprinkle flour over the vegetables and stir to coat evenly. Cook for 1 minute to remove raw flavor.
06 - Gradually whisk in beef broth while stirring constantly to prevent lumps. Incorporate Worcestershire sauce, Dijon mustard, and paprika. Simmer gently for 3 to 4 minutes until sauce thickens.
07 - Reduce heat to low and stir in sour cream until the mixture is smooth and warmed through. Return seared beef along with any accumulated juices to the skillet. Heat gently for 2 to 3 minutes without boiling to avoid curdling.
08 - Adjust seasoning to taste. Serve the beef mixture over the warm egg noodles and garnish with chopped fresh parsley.