In a large bowl, combine the ground meat, onion powder, shawarma seasoning, and mayonnaise. Mix very well until the mixture is smooth and fully combined.

Place about one quarter of the meat mixture onto a sheet of parchment paper and flatten it slightly. Cover with a second piece of parchment that has been lightly sprayed with oil, then use a rolling pin to roll the meat very thin, making sure to leave about one inch of parchment uncovered at one end. Peel off the top sheet of parchment. Starting from the side without meat, fold the parchment up with the meat inside, then place it on a baking sheet. Repeat with the remaining meat.

Bake in a preheated oven at 400 degrees Fahrenheit (200 degrees Celsius) for 30 minutes. Let cool slightly, then carefully unroll the parchment. Use two forks to break the meat into pieces.

Serve the doner meat inside a pita or lafa, or over a salad. Fill with chummus, babaganoush, cabbage salad, cucumbers, and tahini.