Add the coconut milk and coconut sugar to a large saucepan and whisk over medium-high heat. Bring mixture to a full boil, then reduce the heat slightly to allow the mixture to continue to cook at a managed boil. Be sure to whisk frequently (or constantly) to avoid the coconut milk from separating or clumping up.

Cook and whisk until caramel has thickened and is one half to one third of its original volume, about 10 to 15 minutes.

Remove from heat and whisk in the salt, butter, and pure vanilla extract. Allow caramel to cool to room temperature. Note that the caramel will continue to thicken as it cools off. Transfer to glass jar, seal, and refrigerate until ready to use. Caramel can be stored in a sealed container in the refrigerator for up to 3 weeks.