Cut each pita on one side and open carefully without breaking the bread (warming it up makes this easier).
To make the filling, in a large skillet fry the onion in oil until golden. Add the meat and fry for about 10 minutes, stirring, crushing, and turning it over, until it changes color. Add the chili pepper, season with salt and pepper, and stir in the spices and parsley. Spread a sixth of the filling into each bread, then press it closed. Brush with melted butter or oil and place on a sheet of foil under the broiler. Broil, turning over once, until both sides are lightly colored.
Cut in half and then into wedges if serving as an appetizer. Serve hot with lemon wedges. Serves 6.