Preheat oven to 350°F (177°C). Grease two 9-inch cake pans, line with parchment paper rounds, then grease the parchment paper. Parchment paper helps the cakes seamlessly release from the pans. (If it’s helpful, see this parchment paper rounds for cakes video & post.)

A large bowl, sift together the flour, sugar, baking soda, salt, and cocoa powder. In another large bowl, whisk together the butter, buttermilk, eggs, beetroot juice,vinegar, and vanilla.

Using a standing mixer, mix the dry ingredients into the wet ingredients until just combined and a smooth batter is formed.

Divide the cake batter evenly among the prepared cake pans. Place the pans in the oven evenly spaced apart. Bake, rotating the pans halfway through the cooking, until the cake pulls away from the side of the pans, and a toothpick inserted in the center of the cakes comes out clean, about 30 minutes.

Remove the cakes from the oven and run a knife around the edges to loosen them from the sides of the pans. One at a time, invert the cakes onto a plate and then re-invert them onto a cooling rack, rounded-sides up. Let cool completely.

Frost the cake. Place 1 layer, rounded-side down, in the middle of a rotating cake stand. Using a palette knife or offset spatula spread some of the whipped cream Frosting over the top of the cake.