Soak 10-12 cashews in hot water for 10 to 15 minutes.Then puree in a blender to a smooth paste along with 1/4 cup water.Keep it aside.
In a blender ,add diced onions, tomatoes, ginger ,garlic and green chilli and blend without adding water to make a smooth puree.Set it aside.
Press SAUTE mode on Instant Pot. Add oil in to the POT.Once hot, cumin (jeera) seeds and let them splutter.Next add the pureed onion-tomato mixture ,cook for around 3-4 minutes until raw smell disappears.
Then add all the dry spices coriander powder, garam masala, turmeric ,red chili powder and salt. Stir to combine.Scrape the bottom and deglaze the pot. This is an important step, to make sure you don’t get the burn notice when you pressure cook.
Add in the sliced mushrooms ,peas and water. Combine gently with the masala.
Place the trivet and then the bowl of rice with water. This way they will both cook together. Big advantage of the Instant Pot is the option to do Pot-in-Pot Cooking or PIP. This means you can cook multiple things at same time.See pictures below for reference.
Close the lid on the pot, and turn pressure valve to SEALING position.Set the pot to MANUAL/PRESSURE COOK (High Pressure) and set timer to 3 MINUTES.
When the instant pot beeps,Let the pressure release naturally for 5 minutes and then do a quick pressure release. Open the lid.
Add cashew cream ,crushed kasuri methi ,coriander leaves ,lemon juice and Mix well.Simmer the curry for 2 to 3 minutes, the curry will thicken.
Mushroom Masala is ready, serve with Naan, chapatis, roti or hot basmati rice.