1. Boil the potatoes in boiling water with a pinch of salt until fork tender. Then, drain potatoes in your colander and transfer to a bowl; mash using a fork. Set aside to cool.
2. Add the cheddar cheese, egg, parmesan cheese, flour, and sage in the bowl with mashed potatoes. Mix well. Season with salt and pepper.
3. Scoop about 2 tablespoons of the potato mixture and form into small logs. Set aside.
4. Prepare the breading by placing the all-purpose flour, eggs, and breadcrumbs in 3 separate bowls.
5. Coat the potato mixture with flour, then eggs, and lastly breadcrumbs. Spray lightly with oil.
6. Preheat your Air Fryer to 400 F (200 C).
7. Arrange the potato croquettes in the Air Fryer cooking basket evenly, but do not overcrowd.
8. Cook the croquettes for 10 to 15 minutes or until golden brown.