Wash rice and soak for 20 minutes. Drain it completely to a colander and set aside
Wash mutton and drain water thoroughly and marinate with marination ingredients and set aside for at least an hour.
Heat a wide pressure pan or non-stick with oil, add the dry spices, sauté till they begin to sizzle.
Add onions, green chilies and fry till they turn brown almost about to caramelize. This is crucial to get a good aroma and taste. There must be enough oil to for the onions to fry.
Add tomatoes, sprinkle salt just enough for the tomatoes to cook easily. Cook till the tomatoes turn fully mushy and the raw smell goes off.
Add half of the coriander and mint leaves, sauté for a min.
Add the marinated mutton pieces, mix well and saute for 2 to 3 minutes. Cook covered on a low flame till the mutton turns soft and tender or cook for 3 whistles in a pressure cooker. Switch off the stove. If cooking in the pan without pressure cooker, stir occasionally to prevent burning. Remember the flame has to be very low otherwise mutton may turn hard. When the pressure goes off, remove the lid. You will be left with a thick gravy. How thick depends on your mutton. If you are left with lot of watery gravy, then evaporate it by cooking for some time.
Add mint, coriander leaves and garam masala. Saute till the good smell of mint and masala comes out. Pour water, bring to a boil. add rice. Adjust salt and cook on a medium flame till almost all the water is evaporated.
Cover and cook till the rice is fully done. If the rice is under cooked and there is not enough moisture, you can sprinkle some water. Alternately you can close the lid of the pressure pan / cooker and cook on a very low flame for just 5 mins. The flame must barely touch the surface of the pan. Do not let the cooker whistle. Alternately you can move the pan on to a old hot tawa. Set the flame to medium and let it cook that way for 10 mins. This way the biryani is not burnt at the bottom.