Preheat your oven to 340°F.
Line two round cake pans.
Mix the dairy-free milk and vinegar together and set aside to thicken.
In a large bowl, mix the wet ingredients together. Sift in the dry ingredients and gently mix until combined.
Divide the batter evenly between the two prepared pans and bake for 20-25 minutes.
Whisk together the frosting ingredients until smooth.
To make the ganache, finely chop the dark chocolate and place it in a bowl. Heat the coconut milk until it just starts to simmer, then pour it over the chocolate. Cover the bowl with plastic wrap and let it sit for 2 minutes. Stir gently with a spatula until smooth. Allow to cool.
Spread the frosting over one cake layer, then pipe some of the ganache in the center. Place the second cake layer on top and frost the entire cake. Use a small spoon to place dollops of ganache around the top edges, letting some drip down the sides. Spread the remaining ganache evenly on top of the cake with an offset spatula. Refrigerate to set before serving.