Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.
In a large mixing bowl, combine the halved Brussels sprouts with the minced garlic, olive oil, salt, black pepper, and red pepper flakes (if using). Toss everything together thoroughly.
Evenly spread the Brussels sprouts out in a single layer on the prepared baking sheet.
Roast the Brussels sprouts in the preheated oven for about 20-25 minutes, tossing halfway through.
During the last five minutes of roasting, sprinkle the grated Parmesan cheese over the Brussels sprouts.
Once the cheese is melted and golden, remove the baking sheet from the oven.
Garnish the roasted Brussels sprouts with freshly chopped parsley before serving.
Notes
Serve in a large bowl or platter, drizzling extra olive oil over the top if desired.