Preheat your oven to 425°F (220°C) and line a baking sheet with parchment paper.
In a large bowl, toss the halved Brussels sprouts with olive oil, minced garlic, garlic powder, onion powder, red pepper flakes, salt, and pepper until they are well coated.
Spread the Brussels sprouts evenly on the prepared baking sheet, cut side down, to ensure maximum crispiness.
Roast in the preheated oven for 20-25 minutes, stirring halfway through, until they are golden brown and crispy.
Remove from the oven and immediately sprinkle the grated Parmesan over the Brussels sprouts while they are still hot. Return to the oven for an additional 2-3 minutes until the cheese melts slightly.
Remove from the oven, garnish with fresh parsley, and serve immediately for maximum crispiness and flavor.