Saute onion on low flame until nicely carmelized taking care not to burn the onions.
Add tomatoes and seasonings, stir.
Add uncooked rice and herbs. If using whole chicken then stuff with rice mixture and layer pan with remaining rice. If not stuffing the chicken simply layer a large roaster pan with rice mixture and add water to cover. Place chicken over rice and cover well. After an hour turn over chicken and add more water if needed. Cover again and cook until tender (approximately another two hours).