Cut cooked, cooled and peeled beets into quarter size pieces. Place cut beets and avocados into food processor and whip together. Add the softened coconut butter, coconut milk, maple syrup and vanilla extract and blend. Slowly add the cocoa powder and blend into the ingredients. Ladle the mixture into the spring form pan, on top of the chilled crust. Chill for 15 minutes to firm the mousse.