Please read over the recipe and instructions fully before getting started as well as the above blog post which contains more detailed instructions, images, and tips.
Preheat your oven to 180°C (356°F). Line the base of two 8" cake tins with a circle of parchment paper and spray the sides with oil spray.
Add the plain flour, soft brown sugar, cocoa powder, baking powder, and sea salt to a large mixing bowl, whisk and set aside. To make the vegan "buttermilk" add the soy milk and apple cider vinegar to a jug, stir and allow to sit for 10 minutes.
Add the vegan buttermilk mixture, sunflower oil, vanilla extract, and hot coffee to the bowl with the dry ingredients and whisk carefully to combine. Do not overmix the batter.
Divide the batter into the lined cake pans and bake for 30-35 minutes. Check they are ready by inserting a skewer, it should come out clean. Allow the cakes to cool in the tins for 15-20 minutes and then carefully turn them out onto a cooling rack to cool further. Refrigerate the cakes in an airtight container until ready to use. Chilling the cakes for a few hours (or overnight) makes them easier to work with and decorate.
Using a serrated knife, carefully cut the domes from the tops of the cakes if there are any to get them as even as possible. If desired, you can leave the dome on the top cake, just like I did in the pictures shown. Place a tiny amount of frosting on a cake turntable and secure the first sponge layer on top of it.
Use an offset spatula/pallet knife to spread a layer of the frosting on top of one cake and top with the other cake. Spread or pipe the remaining buttercream around the sides and top of the cake.
Keep the cake at room temperature on the day of serving. If you plan on serving it at a later stage, place it in an airtight container and refrigerate. It will store well for 4-5 days.
Nutritional information is based on the cake without buttercream
Measure the recipe in grams: As with all baking, measuring with a kitchen scale will always give you the most accurate results.
Preheat your oven properly: The temperature of your oven affects the texture, flavor, and browning of the cake. So it's important to allow enough time for it to heat to the correct temperature. I usually aim to preheat the oven a good 30 minutes before baking.
Don't overmix the cake batter: Over-mixing the batter can cause the gluten to become overworked. This can lead to a gummy and tougher consistency, not ideal for cakes!