Wash 1 cup of toor dal and then add it to a stove-top pressure cooker along with ½ teaspoon turmeric, 1 teaspoon salt and 3 cups of water. Cook for 5 whistles on a medium-high flame, then lower the heat to medium-low and let it cook for another 5 to 6 minutes.Once the pressure releases naturally, open the cooker and mash the cooked dal lightly with a potato masher. Set aside.If using an Instant Pot, pressure cook for 9 minutes on high pressure and let the pressure release naturally.