Cut the Mozzarella cheese block into approximately 16 sticks, about ½-inch thick. Or if you’re using string cheese sticks then cut them in half.
Mix chili flakes, Italian seasoning, salt and black pepper powder with the panko bread crumbs on a wide plate.
In a shallow bowl, add all-purpose flour. In another shallow bowl, beat the egg.
Working with one stick of mozzarella at a time, coat it in flour, then dip it in egg and finally coat it in panko mixture making sure all sides are covered and coated well.
Arrange the coated mozzarella sticks on a plate and place them in the freezer for at least 30 minutes.
Preheat the air fryer for 5 minutes at 350°F (180°C). Line the basket with parchment paper and arrange the coated mozzarella sticks without overcrowding. Cook for 5 minutes then toss and cook for another 3-4 minutes or until golden brown.