Wash the cauliflower and pat it completely dry. Cut the head into medium-sized florets — not too big or too small.
Place the florets in a large bowl. Add olive oil and toss gently so each piece gets lightly coated. Sprinkle in the garlic powder, paprika, salt, pepper, and cornstarch if you’re using it.
Set your air fryer to 390°F (200°C). Spread the cauliflower in the basket in a single layer. A little overlap is fine, but try not to pile it up.
Air fry for 14–18 minutes, shaking the basket halfway through.