Preheat oven to 400 degrees. Cut bottoms & loose leaves off of Brussels sprouts. At this point you can halve or quarter the brussels sprouts if you want.

Place the brussels sprouts in large Ziploc bag. Pour in the olive oil. Close the bag (make sure it's sealed) and shake well until brussels sprouts are coated.

Spread out the brussels sprouts on baking sheet lined with foil or a silicone baking mat. Sprinkle with Parmesan cheese, salt & pepper. Roast for 20-24 minutes, stirring once. Let cool for 5 minutes and serve.