2 (16 oz.) pkgs. frozen flounder fillets, thawed
1/2 c. spaghetti sauce
2 tbsp. finely chopped onion
4 oz. shredded mozzarella cheese

Pat fish dry with paper towels. Arrange fillets in single layer in microwave safe dish. Sprinkle with salt. Mix sauce with onions. Pour over fillets. Microwave, covered, on high for about 7 minutes (individual microwaves vary so adjust). Sprinkle with cheese. Return to microwave until cheese melts. Let stand a few minutes before serving.