Grease the cake tins. Grease the cake tins, 4 x 23cm round spring-form tins (Baking 2 cakes at a time)Cut round circles on the baking paper to fit the bottom of the cake tins (you may as well prepare all of them now) Place the circled baking paper down and make sure the top of the tin (where the clip is) sits perfectly over the paper. Lock the top in, turn it over and cut the edges of the paper off. Please see note Note 1 for more on this.Use cooking spray for over the paper as well. Flour the tins and set aside.
Heat the oven. Heat the oven to 170 C and make sure the rack is in the middle of the oven.
Dry ingredients. Sift the flour and cocoa into a large bowl. Add the baking powder. Add the salt and use a whisk to combine all the dry ingredients together. Set aside.
Sugar & butter. In a separate bowl add the soft butter (below room temperature for better results) and sugar and using a hand held electric mix, beat until well combined. About 1 minute if your butter is soft and 2 minutes if the butter is a little colder than room temp.
Wet ingredients. Add the oil, sugar, vanilla, eggs, cider vinegar and beat using the electric stand mixer. Return the dry ingredients from earlier and add them into the wet ingredients. Add the dry ingredients in 2 to 3 parts alternating with the buttermilk and run the mixer after each addition.
Red Coloring. Add the beet puree (method below) and using a spatula, fold the puree into the batter till well combined and there are no white parts in the batter. Use the same method for the other 2 cakes but use the beet powder instead of the beet puree if you want the same shades of red as the cake in this recipe.
Batter. Pour the batter between the two prepared cake tins and place in the middle shelve of the oven to bake.
Baking. After 18 to 20 minutes of baking check the doneness with a toothpick. If if comes out clean (probably will) take them out and leave them to cool. If the toothpick is damp leave them another 3 to 5 minutes but not long because they will either burn or dry out. These cakes should be ready in about 20 minutes. With a gentle touch with the tip of your finger on the top of the cake will tell you if its ready. If the cake bounces back its ready.
Cool down. Let the cakes cool down in the tins completely before fiddling! About 10 to 12 minutes. Gently unclasp the side clip and remove the cakes from the bottom tray, peel off the paper and leave to cool until properly cold.