To cook the rice soak it in water for half an hour, then boil 7 cups of water in a big vessel and add bay leaves and salt in it. Add the rice and cook till almost tender. Strain and spread them in a wide tray and let the steam escape.
For chicken, heat oil in a kadhai/wok. Add onions and stir fry till brown. Add ginger garlic paste and mix well. Add tomatoes. Cook till dry. Add yogurt and stir for sometime. Cook it for 10 minutes. Cook till tender. Remove from heat.

Grind all the ingredients for the flavouring masala in a blender to a paste with 1/4 cup water. Strain it through a sieve. Keep it aside.
For assembling the biryani, take a large bottomed pan, sprinkle some curry of the chicken at the bottom. Spread some of the rice. Place 1/2 the chicken pieces on it and wet the rice with some curry. Sprinkle some of the fried onion on it. Sprinkle 2-3 teaspoon liquid flavouring masala.

Repeat by adding rice, then chicken followed by fried onions and flavouring masala and saffron. Mix slightly.

Cover pan with a tight fitting lid and seal the lid with atta dough. Place the pan on heat with a tawa underneath for 1/2 hour to 45 minutes. Serve hot.