Strain the pudding into a new container and stir in butter until it melts.
Place plastic wrap directly onto the surface of the pudding to prevent it from forming a skin, then let chill.
Once chilled, check its consistency. If it is slightly coarse, blend it all together in your blender and strain again before serving.
You can use a variety of sugars to incorporate different flavors. For example, darker sugars create a butterscotch pudding, or you can use syrup to create a maple pudding. To flavor with dry ingredients, simply heat the milk and steep with your choice of coffee, tea, pretzels, popcorn, etc. Let sit, covered, for an hour then strain and re-heat for regular use.