I don't peel them, put them in a foil packet with a clover or two of unpeeled garlic, olive oil
and seal well, on a baking sheet and roast at 400 until they are tender. Then I use a spoon and a fork and peel them while they are still warm, but it doesn't matter really. I use this for all beets and they don't turn odd colors. The greens are delicious as well! I use the garlic and some oj and a little honey and make a dressing with olive oil and toss the greens, then add sliced beets over the top. So delicious! A chef I know always boils his beets, peeled, but I like the roasting message and peeling them post cooking with the spoon, it's so simple.