Roasted Red and Yellow Beets with Balsamic Glaze

"Most beet varieties are available in markets in late spring. Although the most common type sold is deep garnet-red, you'll also find golden beets and even ones with concentric red and white stripes reminiscent of a candy cane. To insure freshness and tenderness, choose small or medium beets with their greens still attached. Remove the greens as soon as you get home, as they will leach moisture from the roots if stored intact over long periods. Garnish the dish with fresh parsley sprigs, if you like...."