Add cashews to milk and blend together to make a smooth paste. Keep aside. Note: Double up milk and cashews if your blender blades are not low and if the paste does not turn out smooth. Making a larger portion can help with bigger blender jars and you can freeze the extra for next time.
Turn the Instant Pot to saute mode and heat ghee. Add cumin seeds, ginger, garlic, and green chili. Saute for a minute. Add onions and cook for 2 minutes stirring a few times. Add spinach, salt, and water. Close the Instant Pot with pressure valve to sealing.
For frozen spinach - Pressure cook on (Hi) for 1 minute
For fresh spinach - Pressure cook on (Hi) for 0 minute
Quick-release and turn off the Instant Pot
Add ½ cup of water(optional) and blend to make a smooth paste using an immersion blender.
Add cashew paste, garam masala, and paneer. Gently stir everything together and cook on sauté mode for 2 minutes or until heated through.