1 cup non fat dry milk powder
1 cup sugar
½ cup boiling water
¼ cup butter (½ stick) melted
Put the dry milk powder and the sugar in a blender. Add the boiling water and the melted butter. Blend on high for about a minute.
Transfer the mixture to a clean jar, cover, and refrigerate overnight.
The next day you will need to stir the mixture again and the final result will be a creamy thickened mixture of homemade sweetened condensed milk that is about equal to the size of a store bought can of sweetened condensed milk.