Stir whole kernel corn, cream-style corn, sugar, egg, and about 3/4 of the melted butter together in a casserole dish. Fold about half the crushed crackers into the corn mixture.
Sprinkle remaining crushed crackers over the top of the mixture and drizzle with the remaining butter.
Bake in preheated oven until beginning to brown, 25 to 30 minutes.