To a small saucepan, add the pizza sauce, Italian seasoning, garlic powder and red pepper flakes and bring to a simmer over medium-low heat, stirring occasionally and cooking down until the sauce is thickened and reduced to about ½ cup. It's done when you can run a spatula through the sauce and it doesn't immediately run back together.
In a large bowl, stir together the mozzarella, parmesan and cornstarch, then add in the chopped pepperoni and pizza sauce, stirring until all of the ingredients are well incorporated.
Place one egg roll wrapper on a flat surface. Portion ½ tablespoon (1 ½ tsp) of filling onto the center of all four quadrants so they're evenly spaced.
Using a pastry brush or your finger, brush a liberal amount of water all around the filling and edges of the egg roll wrapper. Go all the way to the very edges of the filling (this is necessary to make sure the edges seal fully so the filling doesn't burst out while cooking).
Place another egg roll wrapper on top and use your hands to gently flatten out the filling, then seal all four quadrants. Using a pizza cutter or a knife, cut into four separate pizza rolls. Then, trim the edges of each pizza roll on all four sides so there's only about ⅛-1/4-inch around the filling. Make sure the edges are all well sealed.
Repeat with all remaining egg roll wrappers.
Preheat air fryer to 350˚F. Place a single layer of pizza rolls in the air fryer and brush the tops with oil (don't brush too much oil on the edges, just the center, otherwise they may burn too quickly).
Air fry for 6-8 minutes, until golden brown and very crispy. Repeat with remaining pizza rolls.
Serve warm with more pizza sauce and (optional) parmesan sprinkled on top.
