Preheat your oven to 350°F (175°C). Grease two 9-inch round cake pans and line the bottoms with parchment paper.

In a small bowl, whisk together the soy milk and apple cider vinegar. Set aside to curdle, creating a vegan buttermilk.

In a large mixing bowl, sift together the flour, sugar, cocoa powder, baking soda, baking powder, and salt.

Add the vegetable oil and vanilla extract to the vegan buttermilk, then pour the wet ingredients into the dry ingredients. Mix until just combined.

Gradually stir in the hot water until the batter is smooth and well combined.

Divide the batter evenly between the prepared cake pans.

Bake for 30 minutes, or until a toothpick inserted into the center of the cakes comes out clean.

Allow the cakes to cool in the pans for 10 minutes, then transfer to a wire rack to cool completely before frosting.