Place the flank steak into a bowl. Add oil, Italian seasoning, garlic, salt, and pepper. Mix well to ensure the steak is covered with the seasonings. Allow the steak to marinate for 30 minutes, or up to 24 hour in the refrigerator.
Place the steak on a flat surface.
Spread the spinach evenly over steak, leaving a 1/4 inch border at the edge. Cover with red pepper, and then cheese.
Roll up the steak as tightly as you can, ending seam side down. Using a sharp knife, cut the roll in half so that you can better fit it into your air fryer basket.
Set your air fryer to 400F for 8-10 minutes, or until your steak has reached an internal temperature of 145F. It is critical to not overcook skirt steak, so as to not toughen the meat.
Let the steak rest for 10 minutes and serve.
When rolling the steak, make sure the grain of the meat is running horizontally. This makes it easier to roll as well as it makes it less likely that it will unravel while it's cooking.
If you have trouble getting the rolls to stay rolls, you can use toothpicks to ensure that they hold together while cooking them. Just don't forget to remove the toothpicks before serving them.
If the cut of flank steak you have is too thick, you can butterfly the flank steak (cut it in half horizontally). It also helps if you pound the meat flat with a meat tenderizer, rolling pin or whatever else you have in your kitchen that works as a makeshift tenderizer.
I suggest you buy a flank steak and slice it in half horizontally, and use the other half for the German Rouladen-style steak rolls, which will also keep you from having to pound the steak.
Italian Stuffed Flank Steak Rolls https://twosleevers.com/italian-stuffed-steak-rolls/