Squash Casserole

1 pound yellow crookneck squash, cooked and mashed
1/2 cup chopped onion
1 cup grated extra sharp cheese
1 teaspoon sugar
1/2 teaspoon salt
1/4 teaspoon ground black pepper
1/2 cup mayonnaise
1 egg, beaten
1 stick butter, melted
1 sleeve Ritz crackers, crushed

Combine squash, onion, cheese, sugar, salt, pepper, mayonnaise and egg in a large mixing bowl. Stir to mix well. Pour into a greased 2 quart baking dish.

Combine melted butter and crushed Ritz crackers in a medium size mixing bowl. Stir with a fork to combine.

Sprinkle cracker mixture over casserole. Bake at 350 degrees for 35 to 40 minutes.