Preheat oven to 400°F (200°C).
Trim ends of Brussels sprouts, remove loose leaves, and halve or quarter larger sprouts.
In a large bowl, toss Brussels sprouts with minced garlic, olive oil, salt, and pepper until evenly coated.
Spread sprouts in a single layer on a baking sheet, avoiding overcrowding.
Roast for 20-25 minutes, flipping halfway through, until tender and the edges are nicely browned and crispy.
Remove from oven and sprinkle grated parmesan cheese evenly over sprouts.
Return to oven for 3-5 minutes, until cheese is melted and lightly golden brown.
Serve immediately. Garnish with extra parmesan and red pepper flakes, if desired.