Prepare a campfire. Spray the inside (top and bottom) of the pie iron well with cooking spray.
Roll the dough into a rectangle approximately 3 times the length of the pie iron and twice the width. Slice it into 3 even rectangles so that each piece is approximately the length of the pie iron and twice the width.
Lay one half of the pie iron on a flat surface and place one piece of dough into it so that half of it fits snugly about half of it is hanging out.
Top the dough in the cooker with 2 tablespoons pizza sauce, 8 slices pepperoni, and ¼ cup cheese. Fold the excess dough over the filling and pinch the edges to seal it. Place the top half of the pie iron on top and close it. Trim away any excess dough sticking out from the cooker.
Cook over the fire, flipping once, until the pizza dough is golden brown and cooked through, and the cheese is fully melted, 4 to 5 minutes per side.
Remove the pizza pocket from the pie iron and let it cool for at least 5 minutes before eating.
Repeat with the remaining dough and toppings.
Notes
Spray, spray, spray--Spray the inside of the pie iron well with cooking spray to avoid any sticking.
Trim the dough--Trim away any excess dough from the closed pie iron before cooking. If any leaks out while cooking, it will burn, but that's ok. You can just trim it away once the pizza is cooked. Don't attempt to trim it while it's cooking.
Keep it flat--Hold the pie iron as flat as possible while cooking to avoid having the filling leak.
Let it cool--Your pie iron pizza pocket is going to be VERY hot after cooking. Let it cool for at least 5 minutes before eating.