Preheat oven to 400 degrees Fahrenheit. Line a baking sheet with parchment paper and set aside.
In a bowl, combine olive oil, garlic powder, salt, pepper, and parmesan cheese. Add brussels sprouts and toss or stir to coat. Pour brussels sprouts onto parchment lined baking sheet and spread into a single layer. It's okay if some leaves fall off, they can be roasted as well.
Roast brussels sprouts in the oven for 18-22 minutes, or until brussels sprouts are evenly browned. Flip halfway through with a spatula to ensure even browning.
Remove from oven and serve immediately.
*If your brussels sprouts are small, you may want to leave them whole. For medium to large brussels sprouts, slice them in half for quicker cooking in the oven.