2. Place your halved bagels, cut side up, on your work surface. Spread pizza sauce over the bagels, then add shredded mozzarella cheese, and vegetarian pepperoni slices. Place them in the air fryer basket, ensuring that they aren't touching each other, and cook them until the cheese has melted and is bubbling approximately 4 minutes. Repeat in batches until you have cooked all the bagels.