01 - Pour the coconut milk and sugar into a medium saucepan. Add the salt.
02 - Bring to a gentle simmer over medium heat, stirring frequently until the sugar dissolves completely.
03 - Reduce heat to low. Let simmer (do not boil), stirring occasionally, for 35–40 minutes, or until the mixture reduces by about half and thickens.
04 - Remove from heat. Stir in vanilla extract if using. Let cool; it will thicken further as it cools.
05 - Transfer to an airtight container and store in the refrigerator for up to 1 week.