Preheat the oven to 350°F (180°C). If you're not using a non-stick muffin tin, lightly grease the donut pan and set aside.
In a large mixing bowl, mix together the flour, sugar, cocoa powder, salt and baking powder.
In a measuring cup or small bowl, whisk together the milk, melted coconut oil and vanilla.
Pour wet ingredients into dry and stir until just evenly mixed.
Portion the batter evenly among the 6 donut moulds, filling them almost all the way up.
Bake for 13 minutes, until the donuts have risen and a toothpick inserted in to one comes out clean. Take the tin out of the oven and allow to cool or about 10 minutes before removing them from the pan.
In the meantime, prepare the glaze by melting the chocolate. Place the chocolate in a microwaveable bowl and heat it in 15 second intervals, stirring between each one.
Remove the donuts from the pan, place them on a cooling rack and frost them with melted chocolate.