In a small saucepan, combine 60ml (¼ cup) of the coconut milk, the brown sugar, butter, golden syrup and salt. Set the pan over medium heat and, stirring frequently with a silicone spatula, bring the mixture to a boil. Allow the mixture to bubble, stirring constantly, for 5 minutes.
Remove the pan from the heat and stir in the remainder of the coconut milk. Transfer to a heatproof dish and serve as desired.
Notes
If you want to make this recipe dairy-free, simply swap in a vegan butter here. You can also use coconut oil (virgin coconut oil will lend a more "coconutty" taste; if you want to avoid this, use refined coconut oil).
For best results, measure salt by weight, as different salts vary in crystal size and density.