In a large saucepan cover beets with salted water by 1 inch. Simmer beets, covered, 35 to 45 minutes, or until tender, and drain in a colander. Cool beets until they can be handled and slip off skins and stems. Cut beets lengthwise into wedges. Beets may be prepared up to this point 2 days ahead and chilled, covered. Bring beets to room temperature before proceeding. In a large skillet stir together vinegar, syrup or honey, and oil and add beets. Cook beet mixture with salt and pepper to taste over moderate heat, stirring, until heated through and coated well. Sprinkle about half of thyme over beets and toss gently.

Serve beets sprinkled with remaining thyme.