Wash the rice thoroughly and soak in sufficient water for 30 minutes.
Soak the saffron strands in warm milk. Set aside.
Set Instant Pot in saute mode and add ghee.
Add whole spices (black cumin, clove, green cardamom, black cardamom, cinnamon, cloves, pepper, star anise, and bay leaf) and saute for a few seconds.
Add onions and saute until golden brown. Add ginger and garlic and saute for one minute. Add cashews and almonds and mix well.
Add salt, turmeric, and chili powder and mix well. Add chopped vegetables and saute for 1-2 minutes.
Add whisked yogurt. Mix well. Spread the vegetables to cover the IP. After this stage, do not mix.
Add cilantro and mint leaves. Spread them over the vegetables.
Drain water from the soaked rice and add to the IP. Spread evenly. Next, add the saffron milk.
Add 2 cups of water gradually. It is important not to add all the water in one go as this may mix up the layering.
Close the IP lid and seal the vent. Set the Instant Pot to pressure cook mode and cook for 5 minutes. Do a quick release of the pressure.
Veg biryani is ready to be served.