Wash the broccoli thoroughly, then dry it completely with clean kitchen towels or paper towels. Cut the broccoli into evenly sized, bite-size florets, halving any very large pieces so everything cooks at the same rate.

Place the dry florets in a large bowl and add the olive oil, kosher salt, black pepper, and garlic powder. Toss until each piece has a thin, even coating of oil and seasoning.

Preheat the air fryer to 400°F if your appliance requires preheating. Arrange the broccoli in a single layer in the basket, leaving enough room for hot air to circulate.

Air fry at 400°F for about 8 to 10 minutes, shaking the basket or turning the florets halfway through cooking. Continue until the broccoli is tender when pierced and the edges are browned and crisp.

For a slightly less browned and more tender result, cook the broccoli at 375°F for 10 to 12 minutes instead. Check the florets near the end because air fryer models and basket sizes can vary.

Transfer the cooked broccoli to a serving dish and finish with 1 to 2 teaspoons of fresh lemon juice, 2 tablespoons of grated Parmesan, a pinch of red-pepper flakes, or any combination you like. Serve immediately for the best crisp texture.