Ingredients:
4 cups (1 liter) of full-fat milk or low-fat milk
400 g. white sugar
Preparation:
Add milk and sugar to a small, heavy-bottomed saucepan.
Cook on low heat until sugar dissolves.
Once all the sugar is dissolved, bring the mixture to a boil over medium-low heat. Do not stir once the mixture begins to simmer or it may crack and crystallize.
Simmer gently for about 35 to 40 minutes, or until the milk has taken on a creamy color, reduced by half, and thickened slightly. You may notice foam forming on top, gently skim it off with a spoon. (if there are sugary bits lying around the edge of your pan, don't mix them into your condensed milk, this can break your mixture too)
When ready, remove from the heat and pour into a jar to cool. Let the condensed milk cool completely before putting it on the airtight lid. Just note, it thickens up a lot after a few hours in the fridge.
You can keep it in the fridge for up to a week and in the freezer for up to 6 months.