Wash the beets really well and set out for about 20 minutes to dry. Lay them on a tinfoil and sprinkle with olive oil, salt, and pepper. Wrap them well in the tinfoil and place on a baking sheet. Wrap no more than three beets in each tinfoil pack. Bake in a 425 degree oven until they are fork tender. Could take 45 minutes or more. Time varies depending on the oven.