Coat beets with oil on all sides by brushing on or tossing in a bowl. Place beets on a parchment lined pan so there is space between the slices. Sprinkle beets with a few grinds of sea salt and pepper.
Position rack about 6 inches from the broiler and roast under the broiler on HI for 5-7 minutes on each side, or until fork tender.
Remove from oven and arrange beets on a serving platter. Drizzle with balsamic and sprinkle with feta cheese. Serve with additional balsamic at the table, as desired.