01 - Pour the coconut milk and granulated sugar into a medium saucepan. Add a pinch of salt and stir to combine.
02 - Set the saucepan over medium heat and bring to a gentle simmer, stirring frequently until the sugar has completely dissolved.
03 - Lower the heat to maintain a gentle simmer without boiling. Continue cooking for 35 to 40 minutes, stirring occasionally, until the mixture has reduced by approximately half and noticeably thickened.
04 - Remove the saucepan from heat. Stir in the vanilla extract if using. Allow the condensed coconut milk to cool completely at room temperature; it will continue to thicken as it cools.
05 - Transfer the cooled condensed coconut milk to an airtight container and refrigerate for up to 1 week.