Coconut milk note: when you first open the can of unsweetened coconut milk, it will be separated into solids on top and liquids below. Make sure to take everything out of the can and whisk it well before scooping out the amount needed.
Combine all of the ingredients in a medium sauce pot and start to whisk together slowly over medium to medium-low heat. Whisk until smooth.
Keep stirring slowly as you heat up the sauce just until it starts to simmer. As soon as it begins to simmer (as first bubbles appear), take off heat and serve.