• Trim your steak of any fat and slice it thinly against the grain into about ⅕ inch pieces.
• Season the beef slices with salt.
• In a large skillet over medium-high heat, add olive oil and melt 1 tablespoon of butter.
• Sear the beef strips in a single layer for about 30 seconds on each side, then remove them onto a plate and set aside.
• In the same skillet, melt 2 tablespoons of butter and add the diced onion.
• Cook the onion until it becomes soft and translucent, which usually takes about 3 minutes.
• Add the mushrooms and continue cooking for an additional 3 minutes until they start to soften.
• Stir in the minced garlic and sauté for about 30 seconds until it becomes fragrant.

Making the Sauce

• Sprinkle the flour over the mushrooms, stirring well for 30 seconds.
• Gradually pour in the beef broth to deglaze the pan, scraping any bits stuck to the bottom.
• Allow the mixture to simmer and thicken for about 5 minutes.

Mixing in Flavorings

• Add the Worcestershire sauce, Dijon mustard, and sour cream to the sauce, stirring until everything is well combined.
• Return the sautéed beef strips to the sauce, including any juices left on the plate.
• Stir to combine and let simmer for 1 minute to meld the flavors together.

Serving

• Remove the skillet from heat and serve the beef stroganoff over cooked egg noodles.
• Garnish with chopped fresh parsley or chives.