1 (3/4-pound) flank steak
1 T. cornstarch
1 tsp. olive oil
2 C. thinly sliced onion
8oz. mushrooms, sliced
1/2 C. low-salt beef broth
1/2 tsp. salt
1/4 tsp. black pepper
1/4 C. fat-free sour cream
2 T. finely chopped fresh parsley
2 C. hot cooked long-grain rice

Trim fat from steak, and cut steak diagonally across the grain into thin slices. Combine steak and cornstarch in a small bowl, and toss well. Heat oil in a large nonstick skillet over medium-high heat. Add steak, and sauté 5 minutes. Add onion, and sauté 1 minute. Add mushrooms; cover and cook 2 minutes. Add broth, salt, and pepper. Reduce heat, and simmer, uncovered, 5 minutes. Remove from heat; stir in sour cream and parsley. Serve with rice.