Make a paste of the onions, green chillies, garlic and ginger without adding any additional water.
In the meanwhile, wash and chop the veggies (keep the veg chunks fairly large for a nice bite).
Soak the potato chunks in water till used.
Soak the saffron strands in the warm milk while the veggies are being chopped
Wash mint and coriander leaves
Set IP to SAUTE mode.
Once hot, add oil +ghee (reserving a bit for later), add the whole spices
Saute for 30 seconds
Add the onion paste and saute for 2-3 mins till raw smell disappears.
Now add the spice powders + salt. Saute for another 2 minutes till it coats the onions evenly.
Add the veggies one by one into the Instant Pot.
Saute the veggies well till the masala coats it evenly.
Add the washed and drained mint (and coriander if using) leaves, reserving a few till the end
Add the washed and drained rice and gently mix, taking care not to break the grains.
Now add the yogurt and gently mix so the yoghurt is covered with the masala
Add the rest of the mint leaves now
Add half the saffron soaked milk and gently mix
Tip in the rest of the ghee and oil now
Top with half of the birista and the rest of the saffron milk now
Add water as required . Mix gently
Top with the rest of the birista
Deglaze the pan really well
Cancel SAUTE mode.
Set to PRESSURE COOK (LOW) for 5 mins
Once Pressure drops, do a quick release
When the pin falls, wait for 4-5 more mins and open the lid.
Fluff up the biryani with a fork / light ladle.
Serve hot / warm with some raita / papad on the side.