Start with the frosting: Scoop out the solid coconut cream from the top of the chilled coconut milk. Heat this cream until it’s almost boiling. Place the dark chocolate in a bowl, then pour the hot coconut cream over it. Cover the bowl with a towel and let it sit for 5 minutes to melt the chocolate. Stir until smooth, then let it cool and thicken while you prepare the cake.
Preheat your oven to 340°F (170°C) and line three 6-inch round cake pans with parchment paper.
In a small bowl, mix together the dairy-free milk and vinegar, and set aside to thicken.
In a large bowl, sift together the self-rising flour, cocoa powder, baking powder, and baking soda.
In a separate bowl, mix the coconut yogurt, coconut oil, and the thickened milk mixture.
Pour the wet ingredients into the dry ingredients and gently mix until just combined. Be careful not to overmix.
Divide the batter evenly between the three prepared cake pans. Bake for 20-25 minutes, or until a toothpick inserted into the center comes out clean.
Once the frosting has thickened and cooled, transfer it to a stand mixer and whip until it’s light and creamy.
After the cakes have cooled completely, spread the frosting between the layers and over the top.