In a colander, add whole moong lentils, black gram lentils, and kidney beans, then wash under running water for a few minutes. In a large bowl, mix lentils and kidney beans with 5 cups of water. Let them soak for 4 hours or overnight.
Soak cashews in hot water for 20 minutes then blend them with 1/2 cup water in a high-speed blender to make a paste.
Start the Instant Pot on sauté mode and let it heat up. Add coconut oil and cumin seeds.
When cumin seeds start to splatter, add onions, ginger, and garlic and sauté for about 2 minutes.
Add the tomatoes, cashew paste, dal makhani, garam masala, coriander powder, and salt, then stir and sauté for another 2 minutes.
Add the drained lentils and beans and 3 cups of water and mix well.
Press cancel and close the lid with the vent in the sealing position. Change the pot setting to “Bean/chili,” which will set the timer to 30 minutes of high-pressure cooking. When the pot beeps, do natural pressure release and open the lid once the pressure is released.
Stir in plant-based milk and garnish with cilantro. Serve with naan or rice.