Ingredients:

  • 1.5 lbs sirloin steak, thinly sliced against the grain
  • 2 tbsp butter
  • 1/2 tsp salt
  • 1/2 tsp black pepper
  • 8 oz cremini mushrooms, sliced
  • 1 small shallot, finely minced
  • 2 cloves garlic, minced
  • 1 tbsp olive oil
  • 1 cup beef bone broth
  • 1 tbsp Worcestershire sauce
  • 1 tsp Dijon mustard
  • 3/4 cup full-fat sour cream, room temperature
  • 1 tbsp fresh parsley, chopped

Instructions:

  1. Pat the sliced sirloin dry with paper towels to ensure a mahogany-colored crust.
  2. Heat the butter in a large stainless steel or cast-iron skillet over medium-high heat until foaming.
  3. Add the beef in a single layer—cook in batches if they don't fit in one layer. Sear for 2 minutes per side until browned and reaches an internal temperature of 145°F (63°C); remove beef to a plate and let rest for 3 minutes.
  4. In the same pan, add olive oil if needed. Toss in the mushrooms and sauté until they release their moisture and turn golden brown.
  5. Stir in the minced shallots and garlic, cooking for 1–2 minutes until fragrant and translucent.
  6. Pour in the beef bone broth, scraping the bottom of the pan with a whisk to release the browned bits (fond). Season with the 1/2 tsp salt, adding a pinch more if using standard beef broth.
  7. Stir in the Worcestershire sauce and Dijon mustard. Let the liquid simmer and reduce by about one-third to concentrate the flavors.
  8. Lower the heat to low. Slowly whisk in the room-temperature sour cream until the sauce is smooth and glossy.
  9. Return the seared beef and any accumulated juices to the pan. Gently fold for 1 minute until the beef is heated through and coated in the sauce.
  10. Remove from heat immediately to prevent curdling and garnish with chopped parsley.