1 to 2 lbs. beef tenderloin
4 to 5 tbsp. butter
16 to 18 oz. sour cream
1 onion, sliced
1 pkg. mushrooms, sliced
1 pkg. Lawry's/Schilling stroganoff seasoning

In Dutch oven, cook beef with butter and onions until beef is tender. Add water if necessary. You should have 1 1/2 to 2 cups of broth from beef. Add seasoning mix, sour cream, and mushrooms. Cook until mushrooms are tender. Serve over egg noodles.