In a large bowl sift together the cocoa powder, flour and baking powder. Mix in the sugar and then set to one side.
In a food processor puree the cooked beetroot. Add the eggs one at a time to the beetroot and continue to blend.
Add the oil and vanilla and blend until smooth.
Make a well in the centre of the dry mix and add the beetroot puree. Lightly mix together and divide between 12 muffin cases, making sure they are about 2/3 full.
Bake in the pre heated oven for about 25 minutes or until firm to the touch when pressed lightly with a finger.
Allow to cool on a wire rack and finish with a dusting of icing sugar.