Add coconut milk, brown sugar and cocoa powder to a small sauce pan
Whisk the ingredients together and bring to a boil - be careful not to let the mixture boil over the edge of the pan
Once boiling, reduce to a simmer
Simmer uncovered for 14 minutes, whisking occasionally
Remove the pot from heat and allow to cool for a minute before whisking in the peppermint extract and salt
Allow the syrup to cool completely then place in a glass jar and store in the refrigerator for up to 2 weeks
Notes
You can use evaporated milk or sweetened condensed milk in place of the coconut milk. If you use sweetened condensed milk, it will make the syrup quite a bit sweeter, but that doesn't bother me.
You can use coconut sugar or white granulated sugar in place of the brown sugar