Beef Stroganoff - cooking recipe

Ingredients

2 1/2 to 3 lb. beef round steak (1/2 inch thick)
instant meat tenderizer
3 Tbsp. butter or margarine
1 onion, halved and thinly sliced
1 Tbsp. flour
1 c. beef bouillon
1 tsp. prepared mustard
1/2 c. sour cream (at room temperature)
1 (4 oz.) can mushrooms
egg noodles, cooked

Preparation

Cut steak crosswise in 1/4-inch strips.
(To make slicing easier, you may place steak in freezer for about 30 minutes or until ice crystals begin to form.)
(If desired, slice meat very thin, then tenderizer may not be necessary.)