1-First, gather and prep your ingredients. Thinly slice 1 pound of top sirloin steak, chop half a medium onion, slice half a pound of brown mushrooms, and mince 1 garlic clove. This setup makes cooking smooth and efficient.

2-Next, heat a large pan over medium-high heat and add 2 tablespoons of olive oil. Once hot, cook the beef strips in a single layer for 1 minute per side until browned, then set them aside to keep them tender.

3-Now, add 2 tablespoons of unsalted butter to the pan along with the chopped onion and sliced mushrooms. Sauté for 6 to 8 minutes until soft and lightly browned, building a flavorful base for the sauce.

4-Stir in the minced garlic and cook for 1 minute, then mix in 1 tablespoon of all-purpose flour and cook for another minute to thicken. Pour in 1 cup of beef broth and 3/4 cup of heavy whipping cream, simmering for 1 to 2 minutes until it starts to thicken.

5-Temper 1/4 cup of sour cream by mixing in a bit of the sauce first, then add it to the pan along with 1 tablespoon of Worcestershire sauce, 1/2 teaspoon salt, and 1/2 teaspoon black pepper. Simmer until creamy, then return the beef to heat through.

6-Serve over 8 to 12 ounces of egg noodles for a complete meal. For tender results, sear the beef quickly and temper the sour cream to avoid curdling, as this keeps everything smooth.