Place a rack in the upper third of your oven and preheat the oven to 400°F.
For easy clean up, since honey makes the vegetables yummy and sticky, line your baking sheets with foil or parchment paper. Place the Brussels sprouts in the center. Top with the honey, vinegar, mustard, oil, salt, and pepper.
Toss to coat, then spread into a single layer. For maximum crispiness, turn the Brussels sprouts so that they are all cut sides down.
Bake for 20 to 30 minutes, until the Brussels sprouts are charred and crisp on the outside and fork-tender in the center. Halfway through, toss the Brussels sprouts on the pan and rotate the pan 180°F for even cooking. The Brussels sprouts will turn dark and delicious as the honey and balsamic caramelize. Watch carefully towards the end of the baking time, as the cooking time will vary based on the size of your sprouts.
Immediately season with a pinch of additional salt and/or pepper to taste.
Notes
TO STORE: Refrigerate leftovers in an airtight container for up to 4 days.
TO REHEAT: Warm in a 400°F oven or skillet to bring back some crispiness.
TO FREEZE: Not recommended, as the texture can become too soft.