Finely mince / food process the onions, dry them with a towel
Mix onions, spice & meat, either food process, or mix thoroughly
Par-cook the meat on the stovetop, to get some water out. The meat should still easily mush together (like uncooked meat). Then pat down with a paper towel.
Cut pitas in half, and stuff the pita with meat
Shallow fry in fat from the earlier step (or butter or veg oil)
Notes
The main technical challenge in this recipe is getting the pita to be really crispy, as the meat tends to leak grease & water as it cooks. Some relevant tricks are:
Use a very thin layer of meat, thinner than you’d expect.
Par-cook and drain the meat
Pat down the onions
You can also either bake this, or broil this in the oven instead of pan-frying it
You can swap the pitas for fluffier pitas, and then make a non-crisp version of this. It’s more resistant to sogginess, so then you can use more meat, and also you don’t need to worry about draining the meat.