If needed per your model, preheat the air fryer to 400℉ (200℃). Spray the basket or tray with nonstick spray and set aside.
Wash and dry the zucchini. Remove the ends and cut each zucchini in half lengthwise. If working with large zucchini, slice away the seedy center and discard. Slice each half lengthwise into ½-inch-thick planks, then cut the planks into sticks about ½ inch wide and 4 inches long. Gently pat the zucchini sticks with a paper towel to remove any excess moisture.
Prepare the breading station by setting up 3 shallow dishes. In the first dish, combine ¼ cup all-purpose flour with ½ teaspoon kosher salt and ½ teaspoon garlic powder. In the second dish, whisk 1 large egg and 2 tablespoons water. In the final dish, combine ½ cup panko breadcrumbs and ½ cup grated Parmesan, with the remaining ½ teaspoon kosher salt and ½ teaspoon garlic powder, and ¼ teaspoon red pepper flakes.
Dredge the zucchini sticks in the four, shaking off the excess, then dip them into the egg mixture. Allow the excess egg to drip off and then finally coat the sticks in the breadcrumb mixture, pressing to adhere.
Place the breaded zucchini in the greased basket, leaving a bit of space for air to circulate between each fry. Spray the tops of the zucchini fries with cooking spray. Air fry for 7 minutes at 400℉ (200℃). After 7 minutes, remove the basket or tray from the air fryer and flip the zucchini. Spray again with cooking spray and return to the air fryer. Air fry for an additional 4-7 minutes or until the breading is golden. Begin checking at the 4-minute mark, as air fryer models vary.
Serve immediately with your favorite dipping sauce.
Notes
Parmesan: Use freshly grated from a wedge or a tub sold in the deli section, rather than a shelf-stable canister, for the best flavor. Panko: If you don't have panko, use regular unseasoned breadcrumbs.Dairy-Free: Omit the added Parmesan, increase the breadcrumbs to ¾ cup, and add ¼ cup of nutritional yeast and an additional ½ teaspoon of garlic powder to the breading.Gluten-Free: Use an all-purpose 1:1 gluten-free flour and gluten-free panko breadcrumbs.Double the Recipe: It is best not to overlap the zucchini fries in the air fryer, as that will prevent them from cooking evenly. Therefore, if you double the recipe, you will need to air-fry the zucchini fries in batches. Keep the first batch in a 200℉ (95℃) oven while the other batch is being air-friedStorage: Store the zucchini fries in an airtight container in the fridge for up to 3 days. Reheat the zucchini fries in the air fryer at 370℉ (185℃) for 2 minutes per side.