1/2 c. mayonnaise
2 tbsp. flour
2 eggs, beaten
1/2 c. milk
1 (7 oz.) can tuna, drained
8 oz. cheese (Swiss, American, Velveeta), cut into sm. pieces
1/3 c. onion, diced
1 (9 inch) unbaked pie shell

Mix first four ingredients; stir in tuna, cheese, and onion. Pour into crust. Preheat oven to 350 degrees. Bake for 40-45 minutes, or until done.