Cut the mozzarella into bite-size pieces if needed, about 2 centimeters wide, and set aside.

Place the flour in one shallow bowl. Place the whisked egg in a second bowl.

In a third shallow bowl, combine the breadcrumbs, salt, and black pepper and stir to mix well.

Working a few pieces at a time, roll the mozzarella in the flour to coat lightly, then tap off any excess flour.

Dip the floured mozzarella pieces into the egg, turning to coat completely and letting any excess egg drip off.

Roll the egg-coated mozzarella in the breadcrumb mixture, pressing gently so the crumbs cling and form an even crust.

For a double coat, dip each breaded piece back into the egg, then again into the breadcrumbs, pressing to create a thicker coating.

Arrange the breaded mozzarella balls in a single layer on a plate or tray and refrigerate for 10 to 15 minutes to firm up.

While the mozzarella chills, preheat the air fryer to 375°F.

Lightly spray the air fryer basket with cooking spray or a light mist of neutral oil.

Place the chilled mozzarella balls in a single layer in the basket with a little space between each one so air can circulate.

Air fry at 375°F for 5 to 6 minutes, shaking the basket once halfway through, until the coating is golden and the cheese is just starting to soften.

Remove the mozzarella balls from the air fryer and serve immediately with warm marinara sauce and cool ranch dressing for dipping.