Soak cashews in lukewarm water for 10 minutes. Do not skip this step as it will ensure a creamy gravy consistency.
Drain and transfer them to a blender jar along with ginger paste, garlic paste, poppy seeds, and onions. Grind to make a smooth paste. Transfer to a bowl.
To the same blender jar, add the tomatoes and green chillies. Grind to make a smooth puree.
Turn on the Instant pot in saute mode. Add oil or vegan ghee and once its hot, add the onion paste. Cook for 30 seconds.
Crush kasuri methi between your palms and add it to the pot. Mix and cook for another 30 seconds.
Then add the tomato puree to the pot along with salt. Mix and cook for 30 seconds.
Add green peas next and half cup of water. Remember, mushrooms will release water as well.
Add the turmeric, coriander powder, paprika and garam masala.
Rinse the button mushrooms and then add it to the pot. Give it all a good mix. There is no need to add more water.
Cancel the saute mode. Close the lid with the valve in sealing position. Pressure cook in manual mode for 4 minutes. Release pressure manually.
Open the lid and add sour cream. Lastly garnish with cilantro. Mix and serve.