Preheat a 10-inch skillet, uncovered, over medium heat for 2 to 3 minutes.

Melt 1 Tbsp. butter in the skillet.

Add 1 1/2 lb. thinly sliced round steak and 1/4 c. chopped onion to the skillet.

Brown the steak and onion for about 5 minutes.

Add 1 beef bouillon cube and 1/2 c. water to the skillet.

Cover the skillet, reduce heat to low, and simmer for 20 to 25 minutes.

Add 1 can cream of mushroom soup, 1/2 tsp. salt, and 1/8 tsp. pepper, stirring to blend.

Cover the skillet and heat for 10 minutes.

Add 8 oz. sour cream, stirring to blend.

Heat thoroughly, but do not boil.

Serve over hot cooked egg noodles.