Preheat the oven to 400 F. Remove the damaged outer leaves on the Brussels sprouts, trim the stems, wash them, and slice them in half. Place them on a baking sheet
Drizzle the olive oil over them
Sprinkle them with minced garlic, salt, pepper, and red pepper flakes. Mix everything until the Brussels sprouts are fully coated with oil and seasonings
Place them cut side down and bake for 10 minutes
Remove the pan from the oven and sprinkle the Brussels sprouts with Parmesan cheese. Return them to the oven and bake for 10-15 minutes more or until cooked through but not overly soft. Serve with extra Parmesan cheese on top, if desired