Preheat the oven to 400°F (200°C).
Prepare the Brussels sprouts by trimming the ends and removing any discolored leaves.
Cut the Brussels sprouts in half, lengthwise.
In a large bowl, combine the halved Brussels sprouts with olive oil, garlic, salt, and pepper.
Spread the seasoned Brussels sprouts on a baking sheet in a single layer.
Roast in the preheated oven for 20–25 minutes or until golden brown and tender.
Sprinkle grated Parmesan over the sprouts in the last 5 minutes of roasting.
If using balsamic vinegar, drizzle it over the sprouts before serving.
Serve immediately while still warm, garnished with additional Parmesan if desired.
