Once cooled, either finely grate or puree beets in a blender (adding orange juice or water to encourage mixing). Measure out 1/2 cup and set aside.
Wrap beets in foil, drizzle on a bit of canola oil, wrap tightly, and roast for one hour or until a knife inserted falls out without resistance. They should be tender. Set in the fridge (in a bowl to catch juice) to cool to room temperature.
Preheat oven to 375°F, remove the stem and most of the root from your beets, and scrub and wash them underwater until clean.