Begin by washing the broccoli florets thoroughly under cool water. Pat them dry with a clean kitchen towel or paper towels.
In a mixing bowl, combine the olive oil, garlic powder, salt, black pepper, and red pepper flakes. Mix well.
Add the broccoli florets to the bowl and toss them in the oil mixture until they are evenly coated.
Preheat your air fryer to 400°F (200°C).
Place the coated broccoli florets in the air fryer basket in a single layer. Do not overcrowd; if necessary, cook in batches.
Air fry the broccoli for 8-10 minutes, shaking the basket halfway through the cooking time for even crisping. Ensure they are crisp-tender and lightly browned.
Once done, remove the broccoli from the air fryer and transfer it to a serving dish. If desired, sprinkle grated Parmesan cheese on top before serving.