Wash your beets and poke using a fork. Place them in a baking dish and cover with aluminum foil. Bake at 200C/400F for about 1 hour. You will know they are done when a fork pokes easily into the beets. When done, let them cool a little, then remove the peel and cut them into cubes.
Blend the oats into oat flour using a food processor or a blender. Add the oat flour into a large bowl.
In the same bowl, sift the cacao powder. Then, add the baking powder and salt. Mix until combined.
Remove the seeds from the dates and place them in the blender/food processor along with the cooked cubed beets. Pour the coconut oil and oat milk. Blend until a beautiful deep purple paste is formed.
Add the beetroot mixture to the dry ingredients and mix to combine.
Place a sheet of parchment paper into a baking dish. Add the brownie mixture and spread evenly. Add walnuts for decoration.
Bake at 180C/ 350F for 25-27 minutes.
Let the brownie cool completely before cutting, as it still cooks while it cools down. Enjoy!