Preheat the oven to 180 C and line a 20 cm spring form cake tin with baking paper.
Place the unpeeled beetroot and oranges in a pan with water and bring the water to the boil.
Reduce the heat to simmer, cover the pan with a lid and leave to cook for around 50 minutes until the beetroot is tender.
Drain the water and set aside to cool.
Peel one of the oranges, leaving the skin on the other. Peel the beetroot.
Roughly chop the beetroot and oranges and place in a blender. Blend enough to combine ingredients and retain some texture.
Use a hand blender to beat the eggs, oil, sugar and vanilla together in a bowl. Stir through the orange and beetroot mix.
Sift the baking powder, almond meal, and flours into the mixture and add the walnuts. Fold the mixture just enough to combine the ingredients but don't overwork it.
Pour the mixture into the cake tin and place on a tray in the oven to bake.
Bake for 50 minutes at 180 C then rotate the cake in the oven,reduce the heat to 170 C and cook for a further 20 minutes or until a skewer comes out clean when tested through its centre.