Preheat oven to 180 degrees C /350 degrees Line two 7 inch / 18 cm cake pans with circles of baking paper. Grease well the pans.
In a large mixing bowl combine coconut sugar, spelt flour, cake flour, cocoa, beetroot powder, baking soda and baking powder. Start whisking with a hand whisk (or with the mixer at a very low speed), until the ingredients are blended. Gradually add the eggs, oil and vanilla and continue whisking If you are using a mixer, you can increase the speed a bit. At the end add the buttermilk, mixed with the vinegar. Whisk just until all ingredients are combined well and the batter is smooth. Do not overbeat!
Transfer the batter to the prepared pans, dividing it in equal halves. Bake about 30-40 minutes or until a toothpick inserted in the centre comes out clean.
Remove the bases from the oven. Let them cool completely before assembling the cake.
In a large mixing bowl combine all ingredients except the beetroot powder. Beat with an electric mixer at high speed until fluffy and smooth.
Optionally divide the frosting in two equal parts and add the beetroot powder to one of them. Beat until the colour is uniform.
Using a large serrated knife, cut horizontally each base into two equal layers. Trim any uneven parts (they will be used for decoration).
Place one layer on a serving plate and put half of the red frosting on top (in case you made two colours, otherwise use about 1/4 of the whole frosting). Place another layer on top and cover it with about 1/2 of the white frosting. Continue the process with the other two layers, alternating the frostings. Cover the cake on top and on the sides with the remaining white frosting.
Decorate as desired. I used artificial flowers and crumbs from the trimmed parts, coloured with some beetroot powder.
If the cake flour is self raising, add only the baking soda and skip the baking powder
Natural cocoa powder (acid) has a lighter colour, while the dutch process (alkaline) is darker. Alternatively you can use dutch process cocoa powder but natural is preferred for this recipe.
If the batter seems too thick, you can add a few tablespoons of water at the end. Add them one by one to avoid making the batter too thin.