Preheat the oven to 325 F. While the oven is preheating, line the bottom of the cake pans with parchment, then grease the sides and bottom of the pans with pan spray or brush with oil.
In a large mixing bowl, sift the dry ingredients (gluten-free flour, cocoa powder, salt, and baking soda) together.
Next in a separate mixing bowl, combine the wet ingredients (vegan buttermilk, olive oil, vanilla extract, brown sugar, and molasses) and mix thoroughly. Once fully combined, pour the dry mix ingredients into the wet mix. Whisk until just combined, be careful not to over mix.
Once the batter is combined, slowly pour the boiling water into the batter while mixing with the mixer. The batter should be runny.
Next, divide the cake batter evenly between cake pans.
Bake at 325 F for 35-40 minutes, or until the cake is just cooked. The internal temperature should be around 210 F.
Pull the layers out and cool on a drying rack for 10 to 15 minutes.
Once cooled, level the tops of the cakes so they stack nicely. Use a serrated knife to do this.
Once leveled off, it’s time to decorate the cake. Using an offset spatula, spread an even layer of frosting over each cake.
Stack the cake layers. Using a spatula, cover the cake with a thin layer of vegan buttercream frosting. Smooth the frosting with a bench scraper. Then chill the cake in the fridge for 5-10 minutes.
Add a second layer of frosting covering the cake and smooth using a bench scraper.
Lastly add any last decorations you want to the cake. Once you are done decorating, then the cake is finished!