Broccoli: Make sure the broccoli is spread out in an even layer so that it gets crispy edges while it roasts (and doesn't end up steaming
Tomato paste: Rub tomato paste on the broccoli before roasting to mimic the flavor of marinara sauce.
Parmesan cheese: It wouldn't be broccoli Parm without it! Coat the broccoli with some of the cheese so it gets browned and crisp in the oven
Breadcrumbs: Any good "Parm" has that crunchy crust. Instead of breading the broccoli, toss it with seasoned, toasted panko breadcrumbs.
Seasonings: Toss the breadcrumbs with garlic powder, onion powder, and dried oregano - same as you would chicken Parm.
If you want a gooey cheesy moment, once the broccoli is done baking, gather in little piles on the baking sheet, sprinkle with shredded low-moisture mozzarella