Not the slow cooker, the one over egg noodles.

Ingredients

1 lb. boneless beef sirloin, cut into 1 inch cubes.
2 T margarine
½ lb. mushrooms, sliced
2 medium onions, sliced
1 clove garlic, minced
2 T margarine
½ cu. water
1 t. instant beef bouillon
1 t. salt
¼ t. pepper
1 cu. sour cream
½ t. prepared mustard
Egg noodles, cooked, drained and buttered

Directions

Heat 2 T margarine over medium heat until melted. Add mushrooms, onions and garlic. Cover and simmer, stirring occasionally, until onions are tender. Remove vegetables and any liquid from skillet.

Cook and stir beef in 2 T margarine over medium heat about 10 minutes. Add water, bouillon, salt and pepper. Heat to boiling and reduce heat. Cover and simmer until beef is desired doneness, about 10 to 15 minutes. Add vegetable mixture. Heat to boiling and reduce heat. Stir in sour cream and mustard. Heat just until hot. Serve with egg noodles.

Note: You can use this recipe with Beef cut from a Chuck roast or steak, but you have to increase the simmering time for the beef to about 1 hour in order to have the beef be as tender as you would like. In this case, refrigerate vegetable mixture after cooking until you add it to the beef.