Preheat an oven to 350 degrees F (175 degrees C). Drain the pineapple chunks, reserving 1/4 cup of the juice.
Combine the flour, sugar, Cheddar cheese, reserved pineapple juice, pineapple chunks, and crushed pineapple in a large bowl. Pour the mixture into a 1 1/2 quart casserole dish. Mix the cracker crumbs and butter in a small bowl, then sprinkle over the pineapple mixture.
Bake in the preheated oven until golden brown, about 30 minutes.
