Preheat oven to 425°F (220°C) and line a large baking sheet with parchment paper.
Bring a large pot of salted water to a boil and cook Brussels sprouts for 10-12 minutes until fork-tender.
Drain the sprouts and pat them thoroughly dry with paper towels to ensure optimal crisping.
Place the sprouts on the prepared baking sheet and use the flat bottom of a heavy glass to compress each sprout to approximately 1/2-inch thickness.
Drizzle evenly with olive oil and season with salt, pepper, and garlic powder.
Roast in the center rack for 15 minutes, then carefully flip each sprout using a spatula.
Sprinkle the Parmesan cheese over the sprouts and roast for an additional 10 minutes until the edges are dark brown and crispy.
Remove from oven and serve immediately while the texture is at peak crispness.