1. Bring a large pot of salted water to a boil for the egg noodles.

2. Pat the beef strips dry with paper towels and season all over with kosher salt and black pepper.

3. In a large heavy skillet, heat the olive oil and 1 tablespoon of the butter over medium-high heat.

4. Working in batches, sear the beef strips until browned on the outside but still slightly pink in the center, about 1–2 minutes per side. Transfer the browned beef to a plate and set aside.

5. Reduce the heat to medium and add the remaining 1 tablespoon butter to the same skillet.

6. Add the sliced onion and cook, stirring occasionally, until softened and lightly golden, about 5–7 minutes.

7. Stir in the sliced mushrooms with a pinch of salt and cook until they release their juices and turn browned and tender, about 6–8 minutes.

8. Add the minced garlic and cook for 30 seconds, just until fragrant.

9. Sprinkle the flour over the onion and mushroom mixture and stir to coat; cook for 1 minute to remove the raw flour taste.

10. Slowly pour in the beef broth while stirring, scraping up any browned bits from the bottom of the skillet.

11. Stir in the Worcestershire sauce and Dijon mustard, then bring the mixture to a gentle simmer; cook for 3–4 minutes until slightly thickened.

12. While the sauce simmers, cook the egg noodles according to package directions until al dente, then drain. Toss the hot noodles with 1 tablespoon butter and a pinch of salt, if desired.

13. Reduce the skillet heat to low. Stir the sour cream into the sauce until completely smooth and creamy; do not let the sauce boil.

14. Return the seared beef and any accumulated juices to the skillet, stirring to coat the beef in the sauce. Warm gently for 2–3 minutes, just until heated through.

15. Taste and adjust seasoning with additional salt and pepper if needed.

16. Serve the beef stroganoff spooned over the buttered egg noodles and garnish with chopped fresh parsley.