Chop the onions and place in a sauce pan together with butter.
When brown, add all the spices together with yogurt and chopped onions.
Fry until a thick gravy forms and then add the chicken to simmer about 45 min.
Soak the rice in water for about 10 min and then half boil it.
When the chicken is tender, place it with the rice in layers and allow it too steam at a very low heat.
After,fry some cashew nuts and onions light brown and when serving the biryani sprinkle the onions and nuts to garnish.
Serve also with salad and raw onions.