Preheat the oven to 400F/200C. Brush a large baking sheet with a little oil.
Either cut the breads in half or cut a slit along the edge on one side around 2 inches in length.
Finley chop the onion, pepper and tomato and crush or finely chop the garlic.
Mix together the ground beef, onion, pepper, tomato, garlic, parsley and spices. Mix everything well so the ingredients are well-distributed - this is often easiest by hand.
Divide the mixture between the breads and fill, taking care not to break the bread, as far as possible, and spreading the filling relatively evenly in towards the edges.
Place the filled bread on the baking sheet and brush either side of the bread with a little oil.
Bake in the preheated oven for approximately 15 minutes, then turn and bake for another 5 minutes, approximately, until the bread is browned and gently crisp on both sides and the meat is cooked through.
Best served warm, or can be served at room temperature - typically served with tahini sauce on the side to dip.