Preheat air fryer to 375 degrees. Place an egg roll wrapper flat on a dry surface. Spread the entire middle section with mustard. Leave the edges without mustard. In a row, a little below the center, place ¼ cup chopped ham and 2 tablespoons cheese. Moisten wrapper edges with water. Fold the sides in toward the middle, and roll up tightly around the filling. Seal with a dab of water. Repeat to make 3 more egg rolls.
To Bake in Air-Fryer: Spray with cooking spray, and place in the air fryer in a single layer. Cook until golden brown, 6–8 minutes total. Turn over halfway at 3-4 minutes.
To Bake in Oven: Preheat oven to 425 degrees. Line a baking sheet with parchment paper or spray with cooking spray. Place egg rolls on a baking sheet. Spray egg rolls with cooking spray. Bake for 12-15 minutes, until golden and crispy on the outside.
This recipe can easily be doubled, tripled, and so on. Leftover egg roll wrappers freeze great. See tips below.