Add lentils, water, salt, turmeric, and squash to the Instant Pot or a pressure cooker. In an Instant Pot, cook for 10 minutes at high pressure. I haven't tested this recipe in a regular pressure cooker, but cook a few minutes longer than you would usually cook dal to make sure the squash cooks through.
To a saucepan, heat oil over medium heat. Add mustard seeds, cumin seeds, and hing. Let that sizzle for a minute.
Add garlic, ginger, and serrano peppers. Stir for 2-3 minutes until the garlic and ginger are no longer raw. Add tomatoes and cook until everything stays together, so about 4-5 minutes.
Add the pressure-cooked dal to the saucepan. Simmer for a few minute in the saucepan. Taste to make sure you like it! Garnish with cilantro and serve with rice.
