I didn't have condensed milk in the house so I googled a substitute. I used a recipe that called for 1 cup fat free powdered milk, 2/3 cup sugar, 1/3 cup boiling water and 3 tbsp butter. It was all combined in a blender. It worked great. I also found a sugar free recipe that I haven't tried but I thought those that can't have sugar might want to try.
Sugar Free Fat Free Sweetened Condensed Milk
1 1/3 cup Nonfat dry milk powder
1/2 cup water
1/2 cup splenda
In glass measuring cup stir together milk powder & water till it's a paste. Cover and microwave on high for 45 seconds or until hot but not boiling.
Stir in Splenda.
Cover and store in fridge. Chill at least 2 hrs before using.
Keeps for 2 weeks and makes 12 oz