Preheat the oven to 400°F.

Add the ground beef, grated onion, garlic, yogurt, cumin, coriander, paprika, oregano, salt, and pepper to a large bowl. Mix until well combined.

Divide the mixture in the bowl into four equal portions.

Place one portion in the center of a sheet of parchment about 12x16. Place another parchment paper the same size on top and use your hands or a rolling pin to roll the beef mixture into a thin rectangle, the shape of the parchment paper..

Starting from the long side, fold the parchment over the meat and roll it tightly until it forms a flat, compact log. Repeat with the three portions of meat.

Place the parchment-wrapped logs onto the prepared baking sheet. Add the onions and tomatoes on the side. Bake for 15 minutes.

Let the logs cool just enough to handle. Unroll, break the meat apart into small chunks or thin slices, and return it to the baking sheet.

Broil for 2-3 minutes, just until lightly golden with crisp edges.

Serve in warm pita with lettuce, tomatoes, pickles, onions, and tahini sauce.