Peel and and chop the beets into 1/2 inch thick pieces . Take an oven proof dish and arrange the beets in a single layer . Cover tightly with aluminium foil and bake in a 350°F (175°F) oven for 30 minutes or till fork tender . Remove from the oven and cool to room temperature.
In a blender pulse the beet till coarsely chopped . Remove measure 1/2 C chopped beets and return to the blender . Slowly add 1/4 C buttermilk to it as needed make a smooth puree. Set aside.
Preheat oven to 350°F (175°F).
Sift the dry ingredients - flour , baking powder, salt and cocoa - together, at least twice . set aside .
Beat the butter until it is light and fluffy . Add the sugar and mix till creamy. To this add the eggs one by one beating it well to incorporate fully after each addition, Mix in the vanilla essence .
Fold in the flour and buttermilk in parts starting and ending with the flour mix. Add the beet puree and gently fold in till incorporated fully .
Divide batter into the 2 prepared cake pans . Transfer into the preheated oven and bake for 25 to 30 minutes or till done . When ready a tooth pick inserted in the middle of the cake will come out dry .
Remove from the oven and place the pans on a cooling rack . Cool in pan .
The beet can be cooked a day or 2 in advance , but make the puree on the day of the bake.
For detailed instructions go to https://oventales.com/red-velvet-without-food-color/ .