Mix flour and sugar in a large bowl. Whisk in milk and then eggs, until well blended. Pour into prepared baking dish. Mix crumbs with remaining margarine. Corn should be refrigerated if not baked immediately.
Crumbs can remain at room temperature, covered.
Sprinkle crumbs over corn. Bake for 40-45 minutes until mixture begins to set but center still shakes when dish is jiggled.