1. **Prepare the Beef:**

– In a medium bowl, toss the beef strips with flour, salt, and pepper until evenly coated. Set aside.

2. **Cook the Pasta:**

– Cook the egg noodles according to package instructions until al dente. Drain and set aside.

3. **Sauté Onions and Garlic:**

– In a large skillet or sauté pan, melt butter over medium heat.

– Add chopped onions and cook until softened, about 3-4 minutes.

– Add minced garlic and cook for an additional 30 seconds until fragrant.

4. **Cook the Mushrooms:**

– Add sliced mushrooms to the skillet and cook until browned and their moisture has evaporated, about 5-6 minutes.

5. **Cook the Beef:**

– Push the mushroom-onion mixture to one side of the skillet.

– Increase heat to medium-high and add the beef strips in a single layer. Cook without stirring for 1-2 minutes to sear the beef, then stir and cook for another 2-3 minutes until browned. Do not overcook.

6. **Prepare the Sauce:**

– Add beef broth, Worcestershire sauce, Dijon mustard, and hot paprika (if using) to the skillet. Stir to combine, scraping up any browned bits from the bottom of the pan.

– Bring the mixture to a simmer and cook for 3-4 minutes to reduce slightly.

7. **Finish the Sauce:**

– Reduce heat to low and stir in sour cream. Cook for an additional 2-3 minutes until the sauce is heated through. Do not let it boil to prevent curdling.

– Taste and adjust seasoning with salt and pepper as needed.

8. **Serve:**

– Serve the beef stroganoff over the cooked egg noodles.

– Garnish with chopped fresh parsley.