In a 2 cup glass measuring cup, combine cold water and Carnation Nonfat Dry Milk Powder, stirring to make a paste.
Cover and microwave on HIGH (100% power) for 45 to 60 seconds or until mixture is hot but not boiling.
Stir in Splenda.
Cover and refrigerate for at least 2 hours before using. Will keep up to 2 weeks in the refrigerator. Use in any recipe that calls for sweetened condensed milk. Makes equivalent of a 12-fluid-ounce can of commercial brand.