Step 1: Prepare the Beef

1. Pat the beef strips dry with paper towels to remove excess moisture. This helps them sear better.
2. Season the beef with salt, pepper, and paprika. Let it sit for a few minutes while you prepare the other ingredients.

Step 2: Cook the Beef

1. In a large skillet or frying pan, heat 1 tablespoon of olive oil over medium-high heat.
2. Add the beef strips in batches (do not overcrowd the pan) and sear them for about 1-2 minutes per side until browned. Remove from the pan and set aside. Repeat with the remaining beef.
3. If needed, add a little more oil between batches.

Step 3: Sauté the Aromatics

1. In the same pan, add the butter and let it melt over medium heat.
2. Add the chopped onion and cook for 3-4 minutes until it becomes soft and translucent.
3. Stir in the minced garlic and cook for another 1 minute until fragrant.

Step 4: Cook the Mushrooms

1. Add the sliced mushrooms to the pan and cook for 5-7 minutes until they release their juices and become golden brown.
2. If there’s any moisture, allow it to evaporate completely before proceeding to the next step.

Step 5: Make the Creamy Garlic Sauce

1. Sprinkle the flour (if using) over the mushroom mixture and stir well. This will help thicken the sauce.
2. Pour in the beef broth, Worcestershire sauce, and Dijon mustard. Stir to combine, scraping up any browned bits from the bottom of the pan.
3. Let the mixture simmer for 5 minutes until it starts to thicken slightly.
4. Reduce the heat to low, then stir in the sour cream and heavy cream, mixing until smooth.
5. Add the beef back to the pan, along with any juices that accumulated, and cook for another 3-5 minutes until the beef is heated through and coated in the sauce.

Step 6: Cook the Pasta

1. While the sauce is simmering, cook the egg noodles or pasta according to the package instructions. Drain and toss with 2 tablespoons of butter.

Step 7: Final Touches

1. Taste the Stroganoff sauce and adjust seasoning with salt and pepper if necessary.
2. Stir in fresh chopped parsley.
3. Serve the Beef Stroganoff over a bed of buttered egg noodles or pasta, garnished with more parsley.