Blend the defrosted corn in blender or food processor until chopped.
Beat the yolks and add other ingredients. Stir together, do not blend in the machine.
Beat the egg whites until they are stiff. Fold into the casserole.
Put into a large casserole dish; dot with butter. Bake one hour and fifteen minutes. Test for doneness with knife inserted in the center. If knife does not come out clean, bake a few minutes longer. Casserole may be refrigerated overnight or frozen before baking. It will take longer to bake if you do either.