2 med. onions, chopped
1/4 c. butter
2 cans (6 1/2 oz. each) tuna, drained
2 c. shredded cheddar cheese
1 c. Bisquick mix
1 1/4 c. milk
1/4 tsp. salt (opt.)
1/8 tsp. pepper
3 eggs
2 tomatoes, thinly sliced

Heat oven to 400 degrees. Grease 8 x 8 x 2 inch square dish. Cook onions and butter until light brown. Sprinkle tuna, 1 cup of cheese and onions into plate. Beat Bisquick, milk, salt, pepper and eggs until almost smooth. Pour mix into plate over tuna. Bake 25 to 30 minutes until knife comes out clean.

Top with tomatoes and rest of cheese. Bake until cheese is melted, 3 to 5 minutes. Cool 5 minutes. Serves 6 to 8.