Partially freeze steak; trim fat from steak. Slice steak diagonally across grain into 2- x 1/4-inch strips.
Coat a large nonstick skillet with cooking spray; place over medium-high heat until hot. Add steak, mushrooms, chopped onion, and garlic; cook 15 minutes or until steak and vegetables are tender. Drain and wipe drippings from skillet with a paper towel. Set steak mixture aside, and keep warm.
Combine water and bouillon granules in skillet. Combine wine and flour; stir well, and add to broth. Stir in margarine and next 4 ingredients. Cook over medium heat, stirring constantly with a wire whisk, until thickened and bubbly. Add reserved steak mixture. Cook over medium heat until thoroughly heated. Remove from heat, and stir in sour cream. To serve, spoon steak mixture over noodles, and sprinkle with green onions.
Light and Luscious