Crumble Beef Into A 1-1/2-Qt. Microwave-Safe Bowl; Add The Onion. Cover And Microwave On High For 3-1/2 To 4-1/2 Minutes Or Until Meat Is No Longer Pink; Drain. Stir In 1-1/2 Cups Tomato Sauce, Water, 1 Tablespoon Of Parmesan Cheese, Salt And Pepper. Cover And Microwave On High For 2-1/2 To 3-1/2 Minutes. Stir In Rice; Cover And Let Stand For 5 Minutes. Remove Tops And Seeds From Peppers; Cut In Half Lengthwise. Stuff With Meat Mixture; Place In An Ungreased Microwave-Safe Shallow 3-Qt. Or 13-In. X 9-In. X 2-In. Baking Dish. Spoon Remaining Tomato Sauce Over Peppers; Sprinkle With Remaining Cheese. Cover And Microwave On High For 10-12 Minutes Or Until Peppers Are Tender. Let Stand For 5 Minutes Before Serving.