In a small bowl, whisk together the olive oil, honey, and 2 teaspoons of balsamic. Pour over the carrots. Season with 1/2 teaspoon salt and a generous grinding of pepper. Toss gently to combine.
Roast the carrots for 10 minutes; toss, and roast for 15 minutes more, or until the carrots are tender and browned in spots.
Transfer to a serving dish and sprinkle a few more drops of vinegar and some sea salt on top.