Ingredients
Method
- Freeze the sirloin for 20 minutes to make it easy to cut. Then cut into thin slices.
- Heat 1 tbsp of olive oil in a large skillet over high heat. Season beef with salt and pepper, then sear quickly in batches until browned (30-60 seconds per side). Remove from the pan and set aside.
- Reduce heat to medium. In the same pan, add the remaining olive oil and chopped onion and cook for 2–3 minutes until softened.
- Add garlic and mushrooms, cooking for another 5–7 minutes until mushrooms release their moisture and begin to brown.
- Sprinkle gluten-free flour over the vegetables. Stir and cook for 1 minute.
- Slowly pour in the beef broth while stirring to avoid lumps. Add Dijon mustard and Worcestershire sauce and bring to a simmer.
- Cook until slightly thickened, about 5 minutes.
- Reduce heat to low. Stir in sour cream until smooth and warmed through (do not boil).
Notes
- Freezing the beef briefly makes slicing much easier.
- Don't overcrowd the pan when searing the beef; work in batches for a good sear.
- Ensure sour cream is at room temperature to prevent curdling when added to the hot sauce.
- Don't overcrowd the pan when searing the beef; work in batches for a good sear.
- Ensure sour cream is at room temperature to prevent curdling when added to the hot sauce.
