Preheat oven to 350 degrees F (175 degrees C). Lightly grease a 1 1/2 quart casserole dish.
In a large saucepan, heat margarine and 1/2 cup sugar until margarine is melted. Mix in flour, then remove from heat. Whisk in evaporated milk, then mix in corn. Pour into prepared casserole dish.
Bake in preheated oven for 60 minutes, until a knife inserted in center comes out clean. Sprinkle 1/4 cup sugar and cinnamon over top.
