First things first, preheat your oven to 350 F (180 C). While the oven is preheating, lightly spray your cake pans with pan spray and line the bottoms with parchment paper.
Next make your vegan buttermilk. Do this by adding 1 Tbsp of lemon juice to 1 cup soy milk. Set aside for 15 minutes to let permeate. Or you can just buy vegan butter milk. Whatever works for you.
Next sift all dry ingredients (Cake flour, cornstarch, baking powder, cacao powder, baking soda, sea salt) in a mixing bowl and mix thoroughly.
In a stand mixer or using a stand mixer, beat the vegan butter and coconut sugar on medium speed. The butter should look fluffy.
Now mix in the remaining ingredients (unsweetened applesauce, vegan yogurt, vanilla extract, beet powder) into the creamed butter. Mix until combined.
Now its time to add the dry ingredients and the buttermilk. Do so, a little at a time alternating between each into the stand mixer on low speed. Do this until combined, do not over mix.
Divide the cake batter into your cake pans. It should be even for all three pans. Then bake in oven for 40-45 minutes. Once thy are baked, check the doneness of your cakes by sticking a toothpick in the center. If you pull it out and the toothpick is clean, they are done. If not, cook and extra couple minutes.
Transfer the cakes to a cooling rack and cool down completely.
Once cakes are cool. It is time to level the cakes. With a long bread knife slice the crest (highest point) of the cake off the top to make it level. You do not have to do this for the top cake.
Now it is time for icing, Spread icing over the top and sides of one cake. Be sure to go easy with frosting, you got two more layers. Now take the second cake and place on top of the frosted cake. Repeat this process until cakes are done and frosted!