Heat the oven to 400 F. Wrap beets in aluminum foil and bake for 40 minutes or until tender. Set aside to cool slightly. Peel the beets and cut beets into medium-sized chunks. In a medium bowl, combine the cooked beets, oil, thyme, salt and pepper. Place on a baking sheet and roast in the oven for an additional 5 to 10 minutes until hot.