Place beetroots, eggs, cinnamon, vanilla, sea salt, cacao powder, Infinity wholefood powder and stevia in a blender or food processor, and process until smooth. Mix in almond meal, baking powder and walnuts.
Line a shallow rectangular baking tin with baking paper. Transfer the mixture into the tin and smooth the top. Bake for 20 minutes or until a skewer inserted into the middle comes out clean. Transfer to a wire rack and allow to cool before slicing and dusting with extra cacao powder.