Soak cashews in hot water for 15-20 minutes while you work on rest of the recipe.
To a blender, add the washed spinach leaves along with chopped tomato, 3 garlic cloves, 1-inch ginger and 1 green chili.Add little water and blend to a smooth paste. I added around 1/4 cup (2 oz) water here to help it blend. Set this aside.
Press the saute button on the Instant Pot, once it displays hot, add the oil and then add the bay leaf and add the remaining 2 garlic cloves (chopped). Saute for 30 seconds or so until garlic starts changing color.
Then add the chopped onion and cook for 3 to 4 minutes until the onions soften.
Add the pureed spinach-tomato-ginger-garlic paste to the pot now and give a stir.Then add the spices- coriander powder, garam masala, turmeric and red chili powder. Also add the salt and cook the spices for 30 seconds.
Add in the sliced mushrooms, and then add 1/2 cup (4 oz) water and stir. Close the pot with the lid and press the manual or pressure cook button. Cook on high pressure for 4 minutes with the pressure valve in the sealing position.Let the pressure release naturally for 5 minutes and then release the remaining pressure manually.
Meanwhile, drain the water from the soaked cashews and then transfer them to a blender along with 3-4 tablespoons water and blend to a smooth cashew paste.
Once the pressure is released manually after 5 minutes, open the lid and then add in the prepared cashew paste and stir. You can press sauté and let the curry simmer for 1 minutes on sauté after adding the cashew paste. You can adjust the consistency of the curry at this point if you want and add more water.
Add in the crushed kasuri methi and stir. Finally squeeze in some fresh lemon juice. Enjoy palak mushroom with roti or rice!
Stove-top Instructions
Follow the same steps by soaking cashews. Blanch the spinach first for 2-3 minutes until the leaves wilt and then transfer it to a blender along with tomatoes, 3 garlic, ginger, green chili and blend to a paste. Heat a pan on medium heat, add oil and then follow the same steps until cooking the onions. Then add the sliced mushrooms and cook until the mushrooms dry out (they will release a lot of moisture initially). Then add the pureed spinach-tomato mixture and the spices. Stir for 1 minute. Then add 1/2 cup water (or as needed) and cover and cook for 6 to 7 minutes on medium-low heat. Add cashew cream, kasuri methi and lemon juice finally and serve.
Notes
If you want you can add coconut milk or heavy cream here as well in place of cashew cream. I would probably add 1/4 cup of coconut milk or 2-3 tablespoons of heavy cream in place of the cashew cream.