Pan-Seared Beef and Mushroom Pan Sauce

By AislePrompt Test Kitchen · Reviewed by AislePrompt Editorial · Published 2026-04-22 · Updated 2026-04-22

A comforting dish featuring tender beef slices simmered in a rich mushroom-infused sauce, perfect for weeknight dinners. This american-inspired beef ready in about 40 minutes blends beef sirloin, olive oil, large onion into a versatile sauce that lifts everything from grain bowls and roasted vegetables to grilled proteins — a small-batch staple worth keeping in the fridge. Each serving lands at about 450 calories and feeds 4, so a small batch covers several meals across the week without taking over the fridge. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Ingredients

• 1.5 lbs beef sirloin
• 2 tbsp olive oil
• 1 large onion
• 8 oz mushrooms
• 3 cloves garlic
• 1/2 cup beef broth
• 1/4 cup sour cream
• 2 tbsp all-purpose flour
• 1 tsp dried thyme
• 1/2 tsp salt
• 1/4 tsp black pepper
• 1 tbsp fresh parsley

Instructions

1. Step 1: Season the 1.5 lbs beef sirloin slices with 1/2 tsp salt and 1/4 tsp black pepper on both sides.
2. Step 2: Heat 1 tbsp olive oil in a large skillet over medium-high heat until shimmering. Add half the beef slices in a single layer and cook for 2-3 minutes per side until browned, then transfer to a plate. Repeat with remaining beef, adding more oil if needed.
3. Step 3: Add remaining 1 tbsp olive oil to skillet, then add the 1 large onion (thinly sliced) and cook for 4-5 minutes until softened and golden.
4. Step 4: Add the 8 oz mushrooms (sliced) and cook for 5 minutes until they release liquid and begin browning.
5. Step 5: Add the 3 cloves garlic (minced) and cook for 1 minute until fragrant.
6. Step 6: Sprinkle the 2 tbsp all-purpose flour over vegetables and stir to coat, cooking for 1 minute.
7. Step 7: Slowly pour in the 1/2 cup beef broth while stirring, then add the 1 tsp dried thyme and 1/4 tsp salt. Bring to a simmer and cook for 2 minutes until thickened.
8. Step 8: Stir in the 1/4 cup sour cream and return the beef to skillet. Cook for 2-3 minutes until heated through and sauce is glossy.
9. Step 9: Garnish with 1 tbsp fresh parsley and serve immediately.