Add all the "Pressure Cook" ingredients with enough water into a pressure cooker, cook for 2 to 3 whistles, and switch off. Let the pressure cool off on its own. (For Instant Pot, pressure cook on high for 7 minutes and Natural Release)
1 cup mung bean, 1 medium-sized onion, 2 to 3 green chillies, 1 medium-sized tomato, ¼ teaspoon turmeric powder, 1 tablespoon coriander powder, 1 teaspoon red chilli powder, 2 to 3 cups water, Salt to taste
Coconut sauce
Add the items listed under "Grind to paste" into a mixie grinder or chutney maker and blend with just enough water into a smooth paste.
½ cup grated coconut, 2 pinches turmeric powder, ¾ teaspoon fennel seeds, ½ cup water
Simmer
Open the pressure cooker and keep it on a low flame. Stir in the coconut paste, salt and more water if it is too thick. (For Instant Pot, cancel the Keep Warm, open the lid and switch on the Saute mode.)
Bring the curry to a boil. Here you can decide the consistency you want the curry to be - if you need it thick, then let it simmer for a while. You will have to stir once in a while to prevent the dal from bubbling and splashing out. Switch off when it reaches the desired consistency.
Tadka (tempering)
In another small pan, heat coconut oil, add mustard seeds and let it crackle, then add the dried red chilli and curry leaves. Pour this into the curry and give it a good stir. Close it with a lid for a couple of minutes for the flavour to get incorporated.
2 tablespoon coconut oil, ½ teaspoon mustard seeds, 2 dried red chillies , curry leaves
Serve hot with freshly crushed green chillies with the rice crepes shown in the images that we call ari doshas, chapatis or plain white rice.
2 green chillies
Notes
Mung bean: This recipe works for both whole and split mung bean, also known as green gram or cherupayar. It is best to use after rinsing and soaking for at least 30 minutes or overnight.