Trim the ends of the brussels sprouts and peel away any bad leaves.
Preheat oven to 425 degrees F. Line a baking sheet with parchment paper. Don’t use a silicone mat because you will be broiling the brussels sprouts for a few minutes at the end.
Boil brussels sprouts in a pot of water for 10 minutes. Drain and rinse. Let it sit in the strainer for 5 minutes to drain completely. Pat dry.
Place brussels sprouts in a large bowl. Add the oil, salt, garlic powder, onion powder, and black pepper. Stir to combine well.
Place on the baking sheet and take the bottom of a glass cup and gently smash each brussels sprout into a disc. Bake for 15 minutes. Remove from oven and carefully flip. Then sprinkle on the parmesan over the top. Place back in the oven for 15 minutes until crispy on the outside and golden on top. Turn your oven to broil and broil for 3 minutes or until everything is golden brown and crispy. Make sure to watch them very carefully so they do not burn. Enjoy hot!