Add the coconut milk to a small saucepan and set over medium heat. Gently heat the milk, swirling every so often, until small bubble begin to appear underneath the surface but it's not quite simmering. Remove from the heat and let stand for 30 seconds.
Add the chocolate, coconut oil and brandy if using to a medium mixing bowl. Pour over the hot coconut milk. Cover the bowl with an inverted plate or cutting board and allow to sit for at least 5 minutes - just to melt the chocolate.
Starting from the middle and working out, use a silicone spatula to stir the chocolate into the coconut milk until the mixture is thickened and glossy and the chocolate is completely melted (see note 2). Move the refrigerator until completely set - about 2 hours.
Add the cocoa powder (see note 1) to a shallow dish. Remove the ganache from the refrigerator. Use a sturdy spoon or tablespoon measure to scoop tablespoon-sized balls from the ganache. Roll the ganache in your hands (see note 3) to make the truffle spherical, then roll it in the cocoa powder. Repeat with the remaining genache.
Notes
You can also roll the truffles in unsweetened desiccated coconut or finely chopped toasted nuts.
If you still have bits of unmelted chocolate, microwave the ganache in 15-second bursts, stirring in between, until the chocolate is completely melted.
If the room or your hands are warm, consider cooling them with an ice pack to make things quicker. Note that these will be more difficult to make on a warm day.