To begin with soak chana overnight or for atleast 8-10 hours.
Pressure cook along with enough water and salt for 5 whistles in low medium flame. Cooked chana should be soft when pressed but not mushy.
Soak saffron in warm milk, mix it well and set aside.
Whisk thick curd and set aside.
Soak basmati rice in water for 10 mins.Rinse well , drain and set aside.
To a pan - heat oil , ghee add cashews fry until golden. Remove and set aside.
Now add sliced onion fry until golden brown and set aside.
Now add all the whole spices along with green chillies, ginger garlic paste. Saute for a minute.
After that add onion fry until golden.
Next add tomato, fry until mushy and raw smell leaves.
After that add red chilli powder, coriander powder, garam masala powder along with mint and coriander leaves. Give a quick saute, do not burn the spice powders.
Add cooked chana along with whisked curd.
Mix it well. Let it start to boil.
When it starts to boil cook covered for few mins until the mixture becomes slightly thick.
The curry has become thick. Switch off and set aside.
To a big pot add 4 cups water along with whole spices like star anise, cinnamon, cardamom, cloves along with salt.Let it boil then add soaked, drained rice.
Cook exactly for 5-6 mins not more than that.
It should break like this and not become soft when pressed. Make sure rice is cooked only till 3/4th done.
Drain water and keep the cooked rice aside.
These steps should be done off the stove. Brush the bottom of the biryani pot with little oil.
Add 3/4 th of prepared chana gravy to the pot.
Now next layer:add rice along with fried onion and half of mint and coriander leaves.
Next add rice as top final layer along with remaining 1/4 portion chana gravy.
Add remaining fried onion,coriander, mint leaves along with essence, saffron milk.
Close with a tight lid.If there is any opening seal with chapathi dough. My lid is tight so sealed just the hole on the lid.
Heat dosa tawa. Keep the flame as lowest as possible.
Keep the biryani pot on the dosa tawa.Dum cook in lowest flame for 10 mins. Switch off and set aside for for 5-10 mins undisturbed.
Finally open,the aroma is just so so good.
Fluff it gently. Do not overmix.
Serve Chana Dum Biryani immediately without mixing much so that the layers are not completely mixed.