1Choose small, firm, bright green Brussels sprouts. Wash them well, trim the tough ends, and remove any discolored outer leaves.
2Cut the sprouts in half (or quarters if large) for even cooking.
3In a bowl, toss the sprouts with olive oil, salt, pepper, and garlic powder (if using) until each piece is well coated.
4Preheat the air fryer to 190°C (375°F) for 5 minutes.
5Place the sprouts in a single layer in the air fryer basket. Cook for 15-18 minutes, shaking the basket halfway through for even crispiness.
6When done, drizzle with balsamic vinegar or sprinkle with grated Parmesan, or both. Serve immediately while hot.