Prepare the marinade and marinate the chicken. Place the chicken thighs in a bowl and sprinkle with seasonings – black pepper, dried garlic, basil and turmeric, pour in the juice of half a lemon and oil. Mix all the ingredients and leave to marinate for 30 minutes.
Start making the sauce. Pour kefir into a bowl, add sour cream and mayonnaise. Season with ground coriander and cumin, add garlic, chopped herbs and salt. Stir the sauce and leave it to infuse for 15-20 minutes.
Heat the coals. Place the chicken on the grill and, turning occasionally, cook the chicken meat on the grill, slightly drying the crust. This will take about 10-15 minutes. Let the meat cool down a little and cut it into small pieces.
Assemble the shawarma. Lay out the lavash and spread it with sauce. Add chicken, lettuce, tomatoes and cucumbers, pour 2-3 spoons of sauce on top. Roll up the shawarma, bend the long edges to the center and twist the lavash with the filling into a large roll.
Brown the shawarma on the grill for 2-3 minutes on both sides, so the lavash becomes crispy and the filling is soaked with sauce.