Make Gyro Meat: Add onion and garlic to a food processor and very finely chop. Add to a bowl along with the ground meat, salt, pepper, bread crumbs, oregano, cumin, and Aleppo pepper. Use clean hands to mix and mash the meat together really well, so it holds together densely.

Bake: Press meat mixture into a 9×5 inch loaf pan. Bake at 325 degrees F for about 50-60 minutes, or until the center registers 165 degrees on a thermometer. Set aside to rest for 20 minutes, then refrigerate for a few hours or overnight for best results.

Slice Meat: Remove meat from pan (reserve the fat drippings) and cut into thin strips, about ⅛ inch thick.

Brown Meat: Heat a griddle, cast iron or skillet over medium high heat. Add some of the meat drippings or a little oil to lightly coat the bottom of the pan. Once hot, lay the meat slices flat in the hot pan and cook for just 1-2 minutes on each side, until browned and crisp.

Assemble Gyros: Serve gyro meat in a warm pita, topped with tomato, onion, lettuce, tzatziki, and feta cheese if desired.