In a medium pot (off-heat) whisk together the coconut sugar (to taste), cacao powder, cornstarch and salt. Add the milk and whisk until everything is dissolved (make sure to get into all the corners where the dry mixture likes to stick). Measure out the vanilla and chocolate to add later on.
Put the pot over medium heat and cook, whisking often, until it reaches a boil (about 4-6 minutes). Reduce the heat to a simmer and cook, whisking, 30 seconds longer—the pudding should look thick but still pourable. Remove the pot from the heat and add the vanilla extract and chocolate. Whisk until the chocolate is completely melted and the pudding looks satiny smooth.
Pour the pudding into a bowl or divide it between individual cups. Cover with plastic wrap, placing the wrap directly on the surface of the pudding (this will prevent a skin from forming). Refrigerate for 45 minutes (or for up to 4 days), to let the pudding set.
Serve the pudding on its own or with a dollop of whipped cream or coconut whipped cream. If you’re feeling fancy, shave some chocolate over top!