Prep the wings: Pat the wings dry with paper towels until the skin looks matte.
Moisture is the enemy of crispiness.
Season and coat: In a large bowl, toss wings with 1 tablespoon oil, 1 teaspoon salt, 1/2 teaspoon black pepper, 1 teaspoon onion powder (optional), and 1 tablespoon aluminum-free baking powder. The baking powder creates a light, crisp shell.
Preheat the air fryer: Set to 390–400°F (200°C). Give the basket a quick spray of oil to prevent sticking.
Air fry, first round: Arrange wings in a single layer without crowding.
Cook for 18 minutes, flipping halfway. If your air fryer is small, cook in batches.
Make the garlic butter: While wings cook, melt 4 tablespoons butter in a small pan over low heat. Add minced garlic and cook 30–60 seconds until fragrant, not browned.
Stir in 1/2 cup finely grated Parmesan and a pinch of red pepper flakes if you like. Remove from heat.
Second round for extra crisp: Increase air fryer to 400°F (if not already) and cook wings 5–7 more minutes, until deep golden and crisp. Internal temperature should reach 165°F.
Toss in sauce: Transfer hot wings to a large bowl.
Pour over the warm garlic-parmesan butter. Toss to coat, then add remaining 1/4 cup Parmesan and a little lemon zest for brightness. Taste and adjust salt.
Garnish and serve: Shower with chopped parsley and a squeeze of lemon juice if you like.
Serve immediately with chilled ranch dressing for dipping.