In a bowl, toss the cauliflower florets with olive oil, salt, smoked paprika, garlic powder, and onion powder until well coated.
Place the seasoned florets in a single layer in the air fryer basket. Cook for 15 minutes at 400°F, shaking the basket halfway through for even browning.
Remove the cauliflower from the air fryer and serve warm. For an extra kick of flavor, squeeze a bit of fresh lemon juice on top if desired. Garnish with parsley.