Preheat oven to 425°F and line a large baking sheet with parchment paper.
In a large bowl, toss halved brussels sprouts with olive oil, minced garlic, salt, and black pepper until evenly coated.
Arrange brussels sprouts cut-side down on the prepared baking sheet in a single layer, leaving space between each sprout for maximum crispiness.
Roast for 25-30 minutes without stirring until the bottoms are deeply caramelized and the outer leaves are crispy and dark golden brown.
Remove from oven and immediately sprinkle with grated parmesan cheese while still hot.
If desired, drizzle with balsamic vinegar just before serving for extra flavor.