In a large mixing bowl, combine the halved Brussels sprouts with minced garlic, olive oil, salt, black pepper, and red pepper flakes if using. Toss well to ensure all the sprouts are evenly coated.
Spread the Brussels sprouts onto a baking sheet in a single layer, cut side down for maximum caramelization.
Roast them in the preheated oven for about 20 minutes, until the outer leaves are crispy and the sprouts are tender.
Remove the baking sheet from the oven, sprinkle the grated Parmesan cheese over the sprouts, and return to the oven for an additional 5-7 minutes, or until the cheese is melted and golden.
Once done, remove from the oven and drizzle with balsamic vinegar for a slight tang.
Garnish with chopped fresh parsley before serving.
Notes
For extra flavor, add more red pepper flakes if desired.