In a medium mixing bowl, whisk** together sugar, dry milk, and hot water until sugar and milk have dissolved and no clumps remain, approximately 2½ minutes. It should be smooth.
Allow to rest and thicken for 10 minutes.
Use immediately or store in a sealed container in the refrigerator for 4-6 days.
Notes
*This recipe makes about 10 fluid ounces, or 13-14 ounces by weight. It replaces one small can of sweetened condensed milk.**To combine ingredients faster, mix for about 1 minute with an electric mixer.
Refrigerate in a sealed container for up to 4-6 days.
For a thicker sweetened condensed milk, whisk in an additional 2 Tablespoons each of sugar and powdered milk.