1 to 1 1/2 lbs. haddock fillets
1 lg. onion, sliced in rings
1 med. green pepper, sliced in strips
1 can (4 oz.) mushrooms, drained
1 sm. can tomatoes, drained (use fresh tomatoes when in season)
6 oz. Mozzarella cheese slices

Layer first 5 ingredients in a glass pan that will fit in your microwave. Cook 15 to 20 minutes on high, turning twice. Drain. Layer cheese on top. Cook on high 4 to 5 minutes or until cheese melts.