Preheat the oven to 425°F (220°C).
In a mixing bowl, toss the broccoli florets with olive oil, minced garlic, salt, black pepper, and red pepper flakes (if using) until well coated.
Spread the coated broccoli evenly on a baking sheet.
Roast in the preheated oven for 15 minutes.
After 15 minutes, remove the tray and sprinkle the grated Parmesan cheese over the broccoli.
Return to the oven and roast for an additional 5 minutes, or until the cheese is melted and the broccoli is tender and slightly crispy.
Remove from the oven, drizzle with lemon juice if desired, and serve immediately.
For extra flavor, consider adding a sprinkle of lemon zest or another dash of red pepper flakes before serving.
Make sure the broccoli florets are of uniform size for even cooking.
This dish pairs beautifully with grilled meats or as a part of a vegetarian meal.