Prepare marinade for the chicken. Combine the lemon juice, olive oil, garlic, salt, pepper, cumin, paprika, turmeric, cinnamon and red pepper flakes in a large bowl, then whisk to combine. Add the chicken and toss well to coat. Cover and store in refrigerator for at least 1 hour and up to 12 hours.
Prepare the white sauce. Combine the yogurt, mayo, lemon juice, lemon zest, basil, parsley, and garlic. Chill 4-5 hours.
When ready to cook, heat oven to 425 degrees. Prepare a rimmed baking sheet with a non-stick baking mat or line with foil and a tablespoon of olive oil or non-stick cooking spray. Add the quartered onion and sliced red pepper to the chicken and marinade, and toss once to combine. Remove the chicken, onion and red pepper from marinade, and place on the pan, spreading everything evenly across it.
Put the chicken in the oven and roast until it is browned, crisp at the edges and cooked through, about 30 to 40 minutes.
While the chicken cooks, prepare the rice pilaf according to package instructions. Keep rice covered until chicken is ready. Then fluff with a fork and serve.
When cooked through, remove the chicken from the oven, allow to rest 2 minutes, then slice into bite-size pieces. Serve the chicken, onion and pepper over rice pilaf, topped with white sauce and naan or pita bread on the side.