2 medium onions, chopped
1/4 cup butter or margarine
2 6-1/2 oz cans tuna, drained
2 cups shredded Cheddar cheese
1 cup Bisquick Baking Mix
1 1/4 cups milk
1/4 teaspoon salt, if desired
1/8 teaspoon pepper
2 tomatoes, thinly sliced
Heat oven to 400 degrees. Grease square baking dish, 8 x 8 x 2".
Cook onions and butter in 10-inch skillet over low heat, stirring
occasionally, until onions are lightly brown. Sprinkle tuna, 1 cup
of the cheese, and the onions in baking dish. Beat Bisquick, milk,
salt, pepper, and eggs with wire whisk or hand beater until almost
smooth, about 1 minute. Pour over tuna mixture, spreading evenly.
Bake until knife inserted in center comes out clean, 25 to 30
minutes. Top with tomato slices and remaining cheese. Bake until
cheese is melted, 3 to 5 minutes. Cool 5 minutes.