1 1/2 lb. sirloin steak
1 1/2 c. sour cream
4 tsp. flour
2 tbsp. prepared mustard
1 1/2 tsp. salt
1/2 tsp. sugar
1/2 tsp. black pepper
1/2 lb. fresh mushrooms
2 lg. onions
Egg noodles
Frozen peas

Place 1 1/2 pound sirloin steak, cut 1/2 inch thick, in freezer for 30 minutes to firm up meat. Meanwhile, make sauce and cook mushrooms and onions.

SAUCE: In medium-size bowl, blend 1 1/2 cups sour cream, 4 teaspoons flour, 2 tablespoon mustard, 1 1/2 teaspoons salt, 1/2 teaspoon sugar and 1/2 teaspoon pepper; set aside.

VEGETABLES: Wipe 1/2 pound fresh mushrooms with towel, and thinly slice. Peel and thinly slice 2 large onions. Heat 2 tablespoons oil in a heavy 10-inch skillet until hot. Add onions and mushrooms and stir. Reduce heat to low and cover pan, cook 15 minutes.

MEAT: Cut steak into 1/4 inch strips by 2 inch lengths. Set aside. Drain mushrooms and onions and wipe out skillet with paper towels. Heat 2 tablespoons oil in same skillet until hot. Add half the meat and toss the sirloin strips constantly for 3-4 minutes until lightly brown. Remove and brown remaining meat.

Put the meat and juices back in skillet; stir in sour cream mixture and drained vegetables. When mixture comes to a boil, set timer and cook for 2 minutes. Serve with noodles and peas.