Slice onion thinly, separate the layers and set aside.
Heat 4 tbsps oil or ghee in a deep pan.
Fry the onions stirring often until deep golden to brown.
Do not burn else they turn bitter. Remove them from oil & set aside.
Cool & pour this oil to the marinade later.
Add yogurt, salt, turmeric, chili powder, biryani or garam masala powder, cardamom powder, green chilli, ginger garlic paste & lemon juice to a mixing bowl.
Mix well & taste this. If needed add more salt or spice.
Next add in chicken & marinate for 2 hours to overnight for best results.
Overnight marination in fridge yields best soft succulent chicken.
Wash rice till the water runs clear. Soak for 30 minutes. Drain & set aside.
Heat 6 to 7 cups water in a pot. Add 1 tsp oil, whole spices & salt.
Taste this. The water has to be slightly salty.
Boil water rapidly for 5 mins to release the aroma of spices.
Add rice & cook till it is ¾ or 75% done.
The center of the rice must be still slightly uncooked.
Do not make the rice mushy. Drain off to a colander.
While the rice cooks, transfer marinated chicken to a heavy bottom casserole or non-stick pan.
Add oil, ½ of the fried onions, mint & coriander leaves. Mix & spread chicken in a single even layer.
Layer the cooked rice evenly, sprinkle fried onions, mint & coriander leaves over the chicken.
Sprinkle ¼ tsp masala powder. Pour the saffron milk all over & then ghee.
Cover the pot with a foil to trap the steam or dum. Then cover with a tight & heavy lid.
Bake for 30 to 40 mins at 390F or 200C in a preheated oven. The timings will slightly vary depending on the depth of the casserole/pot used. Once done, if the chicken is too moist then bake for another 10 mins.
Place this over a thick hot griddle or tawa. Set the flame to medium high such that the flame reaches all over the diameter of the casserole. Cook this way for exactly 20 mins.
Reduce the flame to lowest. Cook for exactly 15 mins. Off the flame. Rest for 20 to 30 mins.
Garnish hyderabadi biryani with fresh chopped coriander leaves & serve with raita.