Combine: In a heavy-bottomed saucepan, whisk milk and sugar together. Bring to a boil on medium-high heat, whisking often (approx. 8-10 minutes).
Simmer: As soon as the steam starts lifting off the milk and sugar is dissolved, reduce to medium-low heat and continue to gently simmer.
Reduce: Add butter, if using, and continue to gently cook until darkened to a creamy color, thickened in consistency, and reduced by half, (approx. 45 minutes), stirring the condensed milk every 15 minutes or so but take care not to disturb vigorously and avoiding the bottom of the pot.
Chill: When the condensed milk has thickened enough to coat the back of a spoon, remove from heat and pour it into a small glass jar. Cool at room temperature, then transfer to the refrigerator.
Notes
Recipe makes 1 cup of sweetened condensed milk. Storage: Store homemade condensed milk in a sealed container in the refrigerator for up to 4 weeks. Bring to room temperature before using and give a quick stir. Helpful Tips:
Continuously simmer condensed milk. It's essential to keep the milk gently simmering for the sugar to properly caramelize and the mixture to thicken. Keep an eye on the stove, checking the condensed milk every 5-10 minutes or so to make sure it doesn't boil over.
The exact cook time may vary depending on the heat and size of saucepan. If it takes more than 10 minutes to bring the milk and sugar mixture to a simmer, increase the heat to medium-high. Likewise, reduce heat if the milk begins to simmer faster.
When stirring and whisking, avoid scraping the bottom of the saucepan to prevent lifting up the cooked milk solids that may have stuck to the bottom.
Stir during cooling to prevent condensed milk from forming a layer on top. Homemade sweetened condensed milk will thicken as it cools especially once chilled in the refrigerator.
Substitutions and Variations:Sweeteners: Use the same amount of coconut sugar, rapadura, or sucanat. If using honey or maple syrup, reduce amount to ½ cup. Milk: Any milk will work but I recommend whole milk as the fat content helps to stabilize the condensed milk. If using reduced fat milk or skim milk, be sure to use the butter. This recipe can also work with a dairy-free milk, such as almond milk, coconut milk, or cashew milk.
Nutrition Information
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