Rinse the lentils well and add them to the Instant Pot along with the turmeric, salt, oil, and water. Close the pressure valve and turn the settings to High Pressure for 7 minutes. Allow the pressure to release naturally for 15 minutes, then release the rest of the pressure.
Lentils on the stovetop
Add the rinsed lentils, 4 to 5 cups of water, turmeric, and salt to a large pot over high heat. Bring to a boil, then lower the heat to medium and cook uncovered until the dal is soft. This will take between 30 to 4 minutes. Depending on how thick you want your soup, you may want to start with 4 cups, then add water if needed. Stir every 10 minutes.
Lentils in an Indian pressure cooker
In a pressure cooker add the rinsed dal, 3 1/2 cups water, salt, and turmeric. Cook over medium-high heat. When the pressure cooker begin to steam, lower the heat to medium and cook for 7 minutes.
TOAST THE SPICES AND COCONUT
While the lentils are cooking, add all the spices (but not the coconut) to a pan over medium heat. Toast stirring frequently for 2 to 3 minutes until the cumin seeds have turned a shade darker and the spices are aromatic. Allow to cool. Grind into a powder in a spice or coffee grinder.
In the same pan toast the coconut over medium heat so that it becomes golden brown. Allow the coconut to cool and then grind in a spice or coffee grinder. Don't be concerned if it gets a bit clumpy due to the oil content of the coconut; that will blend into the dal.
MAKE THE SOUP (MASALA)
Heat a tablespoon of oil in a pan and add the mustard seeds. When they begin to crackle, stir in the curry leaves if using, onion or asafetida, and salt to taste. I use 1/2 teaspoon of sea salt. Stir frequently for 4 to 5 minutes or until the onions are translucent.
Add in the ground spices, coconut, tamarind or lemon, and cooked toor dal along with half of the cooking liquid. Reserve the rest to dilute the dal. Simmer for 10 minutes. Add more dal cooking liquid as needed to give you the desired consistency. If you need more liquid stir in water.
Taste for salt, acid (a bit of lemon or lime juice), and heat (some ground red chili powder or black pepper). Once you have perfected YOUR Goan dal recipe double it and freeze half for a rainy day. Otherwise, it keeps well for 3 to 4 days in the refrigerator.
Lentils: feel free to play with the lentils of your choice for Goan dal. Red lentils (masoor dal) will cook more quickly and give you a smoother dal. Chickpeas (chana dal) will take longer to cook and retain their shape much better.
Vatana: If you want to use dried white or green peas, soak 1/2 cup for 8 hours. Cook in the Instant Pot on High Pressure for 15 minutes, then natural release for 10 minutes. Stovetop cooking will take 40 minutes to an hour using 2 cups of water; check the water level at the 20-minute mark. And for an Indian pressure cooker, add 1 cup of water. Cook for 4 to 5 whistles or until the peas are soft.
Chilies: I find that 1/2 a Kashmiri red chili with the seeds removed gives me just a bit of heat. Feel free to use a hotter dried chili and/or more chilies if you are looking for heat.