In a mixing bowl, add egg, milk, 2/3 cup of cracker crumbs, salt, and pepper. Mix well. Stir in corn, onion, and pimento. Put mixture into a 1-quart casserole dish. Mix butter and remaining cracker crumbs, then sprinkle on top of corn mixture. Bake, uncovered, at 350 degrees for 65 to 70 minutes or until crust is lightly browned.