Put the beets in an ovenproof pan. Drizzle with 2 tablespoons of olive oil, then sprinkle with salt, pepper and sprigs of thyme; toss to coat. Cover with aluminum foil and roast for 25 minutes, or until a knife slides through the beets with ease.
When cool enough to handle, peel the beets and cut into medium-size wedges. Set aside in a medium serving bowl.
In a medium bowl, mix the honey, vinegar, the remaining 3 tablespoons olive oil, salt and pepper; pour over the beets and toss to coat. Taste and adjust the seasoning. Garnish with the mint.