1. If you wish to use mutton or beef you will need to pre-cook the meat with salt, separately in a pressure cooker and then proceed to step#2 under 'Preparing the masala & the curry'. Cooking time of red meat varies upon the quality & quantity used. Please use your judgement here
2. You may skip the poppy seeds if it is unavailable. Use it if possible as it definitely adds to the taste & texture.
3. Ideally for 1 kilo chicken an equal amount of rice is used. But for small families of 2-3 people 1 kilo of rice results in too much biryani, so you may use 1/2 kilo rice instead which is 2-3/4th cups (US standard measure - 1cup = 237ml or 8oz). To avoid confusion I have simply used 3 cups of rice.
4. The reason we are using a mixture of water & gravy is to make the rice flavourful and also the biryani won't spoil fast (unlike the rice that is cooked separately & added).
5. If you do not have/wish to make this biryani in a pressure cooker you may simply use a regular large sized pan (heavy bottomed Indolium, not steel). Just cover it with a well fitting lid or aluminium foil and a weight (mortar & pestle will do) and cook for approx 14 minutes on simmer (cook time varies depending on the quality of rice used). Turn off the flame and let it sit for 5 minutes before you open & stir the rice.
6. While the chicken is being cooked, you may get anywhere between 2-3 cups of gravy. If you have not drained the chicken well after it was cut and washed, you may get extra stock (a slightly watery gravy). Either ways, you can use 3 cups of gravy for 3 cups of rice and then add water to arrive at the full quantity of liquid used to cook the rice. Using more gravy makes the rice more flavourful.