In a large bowl, combine the minced garlic, cumin, coriander, paprika, turmeric, cinnamon, cayenne pepper, salt, and black pepper.

Add the yogurt, olive oil, and lemon juice to the spice mixture and mix well to create a marinade.

Add the sliced lamb to the marinade, ensuring each piece is well coated. Cover the bowl and marinate in the refrigerator for at least 1 hour, or overnight for best results.

Preheat your grill or a large skillet over medium-high heat.

Once hot, add the marinated lamb slices in a single layer. Cook for about 3-4 minutes on each side, or until the lamb is browned and cooked to your desired doneness.

While the lamb is cooking, warm the pita or flatbreads on the grill or skillet for about 1 minute on each side until soft.

Remove the lamb from the heat and let it rest for a few minutes before slicing it into bite-sized pieces.

To assemble the shawarma, place a generous portion of the cooked lamb on each pita or flatbread. Top with sliced onions and fresh vegetables.

Drizzle with tahini sauce or garlic sauce, then wrap the pita around the filling.

Serve immediately, and enjoy your homemade lamb shawarma!