Combine all the ingredients EXCEPT the bread, whisk thoroughly. Add the bread and mix gently. Let stand about 1 hour so the bread soaks in the egg mixture.
Spray a 10X7 baking dish with cooking spray. Spoon the bread mixture in the dish. Bake at 350 degrees for about 35 minutes or until well set and golden in color.
Next, make the rum sauce. In a small saucepan, melt the margarine and add the sugar and milk, stir just until it is combined. Add the flour, cook stirring constantly with a wire whisk until it thickens. Remove from the heat and stir in the rum. Makes about 1 1/2 cups.
Serve the bread pudding warm from the oven, with a drizzle of rum sauce..adults only of course!