Preheat the oven to 350°F (177°C) and prep two 9″ cake pans with nonstick spray or vegan butter and parchment paper. Combine non-dairy milk, apple cider vinegar, and vanilla extract to make vegan buttermilk. Set aside.
Use a large bowl and whisk together the flour, sugar, cocoa powder, baking powder, baking soda, and salt. Carefully add boiling water, oil, and vegan buttermilk (vinegar mixture from Step 1). Mix with a spatula until just combined. *Note: Batter will be loose and thin but this is 100% supposed to be this way.
Evenly split up the cake batter into the prepared pans and bake them together for about 33 - 37 minutes (start checking at 30 minutes) or until a toothpick in the center comes out clean. Let cool for 15 minutes in the pans, then remove and let cool to room temp before frosting.
For the Frosting
In a large bowl cream together butter and cocoa powder for about 1 minute until well-combined.
Add about half of the sugar, about half the of milk and all the vanilla extract. Turn mix on low to combine, then on high to whip the frosting together for about a minute. Repeat adding the rest of the ingredients.
Now check the consistency of the frosting. If it’s too dry, add a tablespoon at a time more dairy free milk until it reaches your desired consistency. If it’s too wet and does not a shape, add a tablespoon more powered sugar at a time until it reaches the right consistency to hold its shape.
Video
Notes
There are step by step photos, instructions, and tips in the body of this post as well as a detailed video to watch below. We highly suggest reading through the post prior to baking for best results.