Step 1

Prep beef:Toss beef strips in flour (add 1-2 extra tablespoons of flour for a thicker sauce).

Step 2

Brown beef:Heat butter in a large skillet over medium-high heat. Brown the beef, 30-60 seconds per side (this cut of beef comes out tough if overcooked). Do not overcrowd the pan - work in batches if needed! Remove the browned beef to a plate, tent with aluminum foil and set aside.

Step 3

Sauté vegetables:Add onion and mushrooms to the hot skillet and sauté until softened, adding more butter as needed.

Step 4

Deglaze pan:Pour beef broth into the pan, scraping any browned bits off the bottom of the skillet. Simmer until it has thickened into a gravy. Add more broth as needed to yield preferred thickness of sauce, and season with salt to taste.

Step 5

Finish sauce:Stir meat back into the sauce and warm through. Stir a litte of the sauce into the sour cream (to warm it up so it doesn’t split!), then quickly stir it into the sauce in the pan. Serve immediately with your favorite sides.