Ingredients:

  • 1.5 lbs (680g) beef sirloin steak, cut into 1/4-inch thick strips
  • 1 tbsp olive oil
  • 1 tbsp unsalted butter
  • 1 large yellow onion, finely chopped
  • 2 cloves garlic, minced
  • 8 oz (225g) cremini mushrooms, sliced
  • 2 tbsp all-purpose flour (plus extra for dusting)
  • 1 cup beef broth (or stock)
  • 1/2 cup dry sherry (or dry white wine)
  • 1 tbsp Dijon mustard
  • 1 tsp Worcestershire sauce
  • 1/2 cup sour cream (full-fat recommended)
  • Salt and freshly ground black pepper, to taste
  • Fresh parsley, chopped, for garnish

Instructions:

  1. Lightly dust the beef strips with flour, shaking off any excess. Season generously with salt and pepper.
  2. Heat olive oil and butter in the skillet over medium-high heat. Brown the beef in batches, being careful not to overcrowd the pan. Remove beef from the skillet and set aside.
  3. Add onion to the skillet and sauté until softened and translucent. Add garlic and mushrooms and cook until softened and browned.
  4. Sprinkle the remaining flour over the vegetables and cook for 1 minute. Gradually whisk in beef broth and sherry, scraping up any browned bits from the bottom of the pan. Stir in Dijon mustard and Worcestershire sauce.
  5. Bring the sauce to a simmer and cook until slightly thickened.
  6. Return the beef to the skillet and cook until heated through.
  7. Remove the skillet from the heat and gently stir in the sour cream. Do not boil after adding sour cream.
  8. Season to taste with salt and pepper. Garnish with fresh parsley and serve immediately.