Cut the stick of margarine into pieces and place all over the top of pudding.
Bake in the preheated 350°F oven for 40 to 45 minutes.
While baking, I melt another stick of margarine in a heavy saucepan, add ½ cup flour and make a paste, add 1 cup evaporated milk and ½ cup water and bring to a boil, whisking as you go.