Heat the oven to 425°F and set out a large rimmed metal baking sheet. Pat the halved sprouts dry, keeping any clean loose leaves.
Toss sprouts and leaves with olive oil, salt and pepper. Arrange the halves cut-side down in one uncrowded layer.
Roast for 20 minutes without stirring so the cut faces brown. Turn the larger sprouts and roast for 5 to 10 minutes more until tender with crisp edges.
Whisk balsamic vinegar and honey in a large serving bowl.
Add the hot sprouts and toss briefly to coat, then serve promptly while the browned leaves still have some crunch.