Start by making your buttermilk. Combine the warm almond milk with apple cider vinegar and set it aside for about ten minutes. This creates a dairy-free buttermilk that helps the cupcakes rise and stay fluffy.
In a large bowl, whisk together the sugar and melted coconut oil until smooth and slightly creamy. You’re not looking for volume here, just a cohesive, glossy mixture. Add the almond milk mixture and gently whisk to combine, followed by the vanilla.
In a separate bowl, whisk together the flour, cocoa powder, baking powder, baking soda, salt. Slowly fold the dry ingredients into the wet in two additions, mixing just until combined. Be careful not to overmix — this keeps the cupcakes light and tender.
Fill your cupcake liners about three-quarters full and bake at 350°F (175°C) for 18–22 minutes, until the tops spring back lightly when touched. Allow the cupcakes to cool completely before filling and frosting.