Brown the Beef:

1. In a large skillet over medium-high heat, warm the olive oil.
2. Add the ground beef, season with a pinch of salt and pepper, and cook until browned, breaking it apart with a spatula. Drain any excess fat if needed.

Sauté Aromatics and Mushrooms:

1. Add the diced onion and minced garlic to the beef. Sauté for 2–3 minutes until the onion softens.
2. Stir in the sliced mushrooms and cook for an additional 4–5 minutes until they are tender and lightly browned.

Create the Stroganoff Sauce:

1. Sprinkle in the flour (if using) and stir for 1 minute to coat the mixture lightly.
2. Pour in the beef broth and add the Worcestershire sauce and Dijon mustard. Stir well and bring the mixture to a simmer.
3. Allow the sauce to simmer for 3–4 minutes until it starts to thicken slightly.
4. Reduce the heat to low, then gently stir in the sour cream. Warm the sauce through—avoid boiling to prevent curdling—then adjust seasoning with salt and pepper.

Serve:

1. Meanwhile, prepare egg noodles according to package directions and drain well.
2. Spoon the creamy beef stroganoff over a bed of hot egg noodles.
3. Garnish with freshly chopped parsley, if desired, and serve immediately.