Preheat the oven to 425 degrees F. Cut the greens away from the beets, leaving about 1/4 inch of stems. (Reserve greens for another use, if desired.) Scrub the beets and place in a baking dish (or lidded ovenproof casserole dish). Add 1/4 inch of water to the dish. Cover tightly. Place in the oven and roast small beets (three ounces or less) for 30 to 40 minutes, medium beets (four to six ounces) for 40 to 45 minutes, and large beets (eight ounces or more) for 50 to 60 minutes. They’re done when they’re easily penetrated with the tip of a knife. Remove from the oven and allow to cool in the covered baking dish. Cut away the ends and slip off the skins.
Roasted beets are wonderful on their own or simply dressed with a vinaigrette. They will keep for five days in a covered bowl in the refrigerator. It is best not to peel them until you plan to eat them, to keep them the most flavorful.