Instructions:
- Combine Milk and Sugar:
- In a medium-sized saucepan, combine the whole milk and granulated sugar.
- Dissolve the Sugar:
- Heat the mixture over medium heat, stirring frequently until the sugar is completely dissolved.
- Simmer the Mixture:
- Once the sugar has dissolved, reduce the heat to low and let the mixture simmer gently. Do not let it boil. Stir occasionally to prevent burning and sticking to the bottom of the pan.
- Simmer the mixture for about 30-40 minutes, or until it has reduced by about half and has thickened to a syrupy consistency.
- Incorporate the Butter:
- Remove the saucepan from the heat and stir in the unsalted butter until it is fully melted and incorporated.
- Add Vanilla (Optional):
- If desired, stir in the vanilla extract for added flavor.
- Cool the Mixture:
- Allow the sweetened condensed milk to cool to room temperature. It will continue to thicken as it cools.
- Store:
- Transfer the cooled sweetened condensed milk to an airtight container and store it in the refrigerator for up to two weeks.