Ingredients

• 600 g / 1.2 lb scotch fillet steak / boneless rib eye (Note 1)
  
• 2 tbsp vegetable oil, divided
  
• 1 large onion (or 2 small), sliced
  
• 300 g / 10 oz mushrooms, sliced (not too thin)
  
• 40 g / 3 tbsp butter
  
• 2 tbsp flour (Note 2)
  
• 2 cups / 500 ml beef broth, preferably salt-reduced
  
• 1 tbsp Dijon mustard
  
• 150 ml / 2/3 cup sour cream
  
• Salt and pepper

• 250–300 g / 8–10 oz pasta or egg noodles of choice (Note 3)
  
• Chopped chives, optional

Instructions

1. Lay the steaks flat and gently pound them with your fist, rolling pin, or mallet until they’re about 3/4 cm (1/3") thick. Slice into 5 mm (1/5") strips, trimming off any large pieces of fat.
2. Season lightly with salt and pepper.
3. Heat 1 tablespoon of the oil in a large skillet over high heat. Add half the beef, spreading it out quickly with tongs. Don’t move it for 30 seconds so it can brown. Flip the pieces as best you can, cook another 30 seconds, then transfer immediately to a plate. (It’s fine if the inside is still pink.)
4. Add the remaining tablespoon of oil and repeat with the rest of the beef.
5. Reduce the heat to medium-high. Add the butter, then the onions. Cook for 1 minute before adding the mushrooms.
6. Cook until the mushrooms turn golden, scraping the pan so all those browned bits dissolve into the mixture.
7. Add the flour and stir for 1 minute.
8. Pour in half the broth while stirring to avoid lumps. Once smooth, add the rest of the broth.
9. Add the sour cream and mustard, stirring until everything is well combined. (If the sauce momentarily looks separated, it will come together as it warms.)
10. Bring the sauce to a gentle simmer, then reduce the heat to medium-low. Let it thicken to the texture of pouring cream, about 3–5 minutes. Season with salt and pepper.
11. Return the beef and any collected juices to the skillet. Simmer for 1 minute, then remove from heat. (Note 4)
12. Serve over noodles or pasta and top with chives if you like.

1. Best beef options:
   Ideal cuts include boneless rib eye (scotch fillet), boneless sirloin, sirloin steak tips, or beef tenderloin.
   Cuts that don’t suit quick cooking—like round steak (topside), skirt, flat iron, or hanger—are not recommended.
2. Flour:
   Any standard flour works. For a gluten-free option, replace with 1 tbsp cornstarch/cornflour.
3. Serving ideas:
   Short pasta shapes are easier to eat with the creamy sauce, but mashed potatoes, rice, or polenta also pair beautifully.
4. Sauce consistency:
   If the sauce becomes too thick, loosen it with a splash of water. Avoid prolonged simmering after the beef is added to prevent overcooking.
5. Storage:
   Keeps 3–4 days in the refrigerator or can be frozen. Thaw fully before reheating gently.
6. Nutrition:
   Per serving (based on 5 servings, excluding pasta):
   586 calories, 37 g protein, 44 g fat, 9 g carbohydrates.