Seafood Tomato Alfredo

1 tbsp. butter

1 sweet onion

1 can of Cream of Mushroom with roasted garlic soup

1/2 cup milk

1 cup diced canned tomatoes

1 lbs. fresh fillets cut into small pieces (flounder, haddock, or halibut)

4 cups cooked linguine

Heat butter in skillet. Add onion and cook until tender. Add soup, milk, and tomatoes. Heat to a boil. Add fish. Cook over low heat 10 min. or until done. Serve over linguine.