Begin by preparing the marinade. In a large bowl, mix the olive oil, minced garlic, cumin, coriander, turmeric, cinnamon, allspice, paprika, cloves, and lemon juice. Add salt and pepper to taste. Combine thoroughly to form a fragrant paste. Ensure the spices are evenly distributed.

Add the chicken thighs (or beef) to the marinade. Use your hands to coat the meat evenly with the marinade. For best results, cover the bowl and refrigerate for at least 2 hours, or overnight, to allow the flavors to penetrate the meat deeply.

Preheat your oven to 180°C (350°F). While the oven heats up, line a baking tray with aluminium foil. You can also prepare the shawarma on a grill or stovetop for a more authentic flavour, adjusting the cooking time accordingly.

Place the marinated chicken on the prepared baking tray in a single layer. If using a grill, ensure the meat is placed over medium heat. Bake the chicken in the oven for 25-30 minutes, turning halfway through, or until the meat is cooked through and slightly charred.

While the meat is cooking, prepare the garnish. Thinly slice the tomatoes, cucumbers, and lettuce. Set them aside in a serving dish. You can also prepare additional garnishes like pickled turnips or onions for extra flavour.

Once the meat is cooked, remove it from the oven and allow it to rest for 5 minutes. This will help retain its juices and make slicing easier. Slice the chicken or beef into thin strips to create the traditional shawarma texture.

Warm the pita breads in the oven or on a stovetop. Spread a layer of tahini sauce or garlic sauce over the pita, if desired. Add the sliced meat and top with the fresh vegetables. You can also sprinkle with some fresh parsley or a squeeze of lemon juice for added zest.

Serve the shawarma hot, wrapped in the pita bread, and enjoy alongside additional condiments like extra sauce, pickles, or a side of fries. For presentation, you can serve the assembled shawarma on a large platter with the garnishes on the side, allowing guests to build their own wraps.