Preheat your air fryer to 375°F (190°C) for about 3 minutes.
Toss the broccoli florets with olive oil, minced garlic, red pepper flakes, salt, and pepper in a large bowl until evenly coated.
Arrange the broccoli in a single layer in your air fryer basket. Work in batches if needed — overcrowding leads to steaming rather than crisping.
Air fry for 8–10 minutes, shaking the basket halfway through, until the edges are golden and slightly charred.
Remove from the air fryer and immediately sprinkle with Parmesan cheese and a squeeze of lemon juice.
Serve right away and enjoy!