Preheat the oven to 180ºC (350ºF, Gas Mark 4). Wash the beetroot and trim the top and bottom of the root without damaging the skin too much.
Place on a baking tray with the oil and water. Tightly cover the baking tray with foil and bake for 45-60 minutes or until the beetroot is tender. Check after 25 minutes and baste with the liquid to ensure they don't dry out (add more water to the tray if required). Set aside to cool before peeling off the skin - wear gloves to protect your hands from staining.