Step 1: Season the beef strips generously with salt and pepper.
Step 2: Heat 1 tablespoon of olive oil in a large skillet or Dutch oven over medium-high heat until shimmering. Sear the beef in batches to avoid overcrowding the pan, about 1-2 minutes per side, until browned. Don’t cook through; we’re just building flavor. Remove seared beef to a plate and set aside.
Step 3: Reduce heat to medium. Add the remaining 1 tablespoon of olive oil to the skillet. Add the sliced onions and cook, stirring occasionally, until softened and translucent, about 5-7 minutes.
Step 4: Add the sliced mushrooms to the skillet. Increase heat to medium-high and cook, stirring occasionally, until the mushrooms have released their liquid and are nicely browned, about 7-10 minutes. This browning develops deep umami flavor crucial for a great beef stroganoff recipe.
Step 5: Stir in the minced garlic and cook for 1 minute until fragrant. Do not burn the garlic.
Step 6: Deglaze the pan with dry white wine or 1/2 cup beef broth, scraping up any browned bits from the bottom of the skillet. Let it simmer for 2-3 minutes to reduce slightly.
Step 7: In a small bowl, whisk together the remaining 2 cups of beef broth with the Dijon mustard, Worcestershire sauce, and all-purpose flour until smooth.
Step 8: Pour the broth mixture into the skillet with the vegetables. Bring to a simmer, stirring constantly, until the sauce thickens. This will take about 3-5 minutes.
Step 9: Return the seared beef and any accumulated juices to the skillet. Reduce heat to low, cover, and simmer for 10-15 minutes, or until the beef is tender. This gentle simmer will finish cooking the beef and infuse it with the sauce’s flavors.
Step 10: Remove the skillet from the heat. Gently stir in the room-temperature sour cream. Stir until fully incorporated and the sauce is creamy. Do NOT bring the sauce back to a boil after adding the sour cream, as it can curdle.
Step 11: Taste and adjust seasoning with salt and pepper as needed. Garnish with fresh chopped parsley.
Step 12: Serve immediately over hot egg noodles, rice, or mashed potatoes. Enjoy your homemade beef stroganoff recipe!