To make your own sweetened condensed milk at home, all you need are milk, sugar, butter, and about two hours of your time.
Simply place milk and sugar in a pot and bring to a boil over medium heat. Reduce to a very low simmer for about two hours until liquid volume is reduced by half. Mix in a tablespoon of butter and remove pot from heat until milk has thickened to desired consistency. Use right way or place in a container with lid in refrigerator until ready to use.
Condensed milk can be used as a topping for toast, coffee, ice cream, and shaved ice, and can also be used for a number of dessert recipes. For a healthier alternative, you can replace milk with coconut milk and sugar with coconut sugar.
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