Preparation

1. Put the 1 cup onions, ginger, garlic and tomato in a blender and whiz to get a smooth puree.
2. Make a paste of the cashews.

Instant Pot Method

1. Turn the instant pot to saute and wait until it displays HOT. Add the oil, followed by the 1/2 cup sliced onions.
2. When the onions start changing color (don't caramelize them completely), add the onion puree prepared in step 1 of prep as well as the powdered spices (turmeric and red chilli powder), and salt.
3. Cook this masala for 5 minutes, adding splashes of water or broth to keep it from sticking to the bottom. If the masala splatters too much, add 1/2 cup water and cover with a glass lid.
4. Cancel the saute mode. Add the sliced mushrooms, mix well and close the lid. Make sure the steam release handle is sealed and set the pot to pressure cooking (high) for 2 minutes.
5. When the timer beeps, wait 5 minutes, then release pressure. Open the pot, add the cashew paste and cook for 5 minutes more. Serve hot with rice or Indian bread.

Stovetop Method

1.  Heat the oil in a karahi or wok and add 1/2 cup onions.
2. Saute the onions until they start changing color. Do not brown them completely.
3. Add the onion paste prepared in step 1 of prep as well as the ground spices (turmeric and red chilli powder) and salt. Add 1/2 cup water or broth, mix well and cover with a lid to avoid splattering. Cook this masala for 5 minutes or so.
4. Add the mushrooms and more water if required and cook for 10 minutes, stirring the mushroom masala gravy a couple of times.
5. Add the cashew paste, mix well and simmer for another 5 minutes. Mushroom masala is ready to be served with fresh Indian bread or rice.