Place onion and butter in 1 1/2 quart microwave-safe dish. Arrange shrimp around the outside of the dish; place mushrooms in the center of dish. Sprinkle with flour, salt and pepper. Cover and cook in microwave on high for 4 minutes. Stir, replace cover and cook 2 minutes. Stir in sour cream. Cook 1 minute or until heated thoroughly. (Do not allow mixture to boil). Serve over cooked rice.
Yield: 6 servings
Per serving: calories 244, calories from fat 153, total fat 17g, saturated fat 10g, cholesterol 153mg, total carbohydrate 5g, protein 17g.