Pulse onion and garlic in a food processor, until finely minced.
1 medium onion, 6 garlic cloves
Add ground lamb, beef and all seasonings. Process until smooth and paste-like (about 45 seconds).
1 pound ground lamb, 1 pound ground beef, 1 tablespoon dried oregano, 2 teaspoons ground cumin, 1 teaspoon dried thyme leaves or ½ teaspoon ground thyme, 1 teaspoon dried rosemary, 2 teaspoons kosher salt, ½ teaspoon black pepper, ½ teaspoon aleppo powder
Pack meat mixture firmly into an 8×8 inch baking dish.
Bake covered for 45 minutes or until internal temperature reaches 165°F.
Let rest for 15 minutes before chilling.
Cover loaf with plastic wrap and refrigerate until completely cold (minimum 2 hours, preferably overnight).
Warm the Pita Bread
Microwave Method: Wrap pita bread in slightly damp paper towels and microwave for about 30 seconds until warm.
Warm pita bread
Skillet Method: Warm pitas in a dry skillet over medium high heat. Add a few drops of water around the pita and warm until soft and pliable, about 15-20 seconds per side.
Assemble the Gyro
Remove chilled meat from the fridge and slice as thinly as possible.
Heat olive oil in a heavy skillet over medium-high heat.
Extra virgin olive oil
Sear meat slices for 20-30 seconds per side until your desired crispiness.
Spread tzatziki sauce generously on warmed pita bread.
Tzatziki sauce
Layer meat slices evenly across pita.
Add sliced tomatoes, red onions, cucumbers, lettuce and feta cheese crumbles.