Preheat oven to 400 degrees.
Cut thin layer from bottom stem of the Brussels sprouts if lightly browned.
Keep very small Brussels sprouts whole, halve others. Remove stray leaves.
Place on a rimmed 18 by 13-inch baking sheet, toss with olive oil and season with salt and pepper.
Roast in preheated oven, tossing once halfway through, until golden brown and tender, about 20 - 25 minutes*.
In a small bowl whisk together balsamic vinegar with honey.
Pour roasted Brussels sprouts into a serving bowl, drizzle balsamic mixture over and toss. Serve warm.
*If after about 20 minutes they haven't browned much you can move the rack closer to broiler and broil just very briefly, about 20 - 60 seconds.