Pressure cook the Cherupayar or green gram with salt to taste along with 1/2 cup of water.
Once pressure cooked, mash the green gram with the back of your spoon (do it when its hot and just removed from the pressure cooker).
In a mixer grinder jar, add grated coconut, green chillies and cumin seeds or jeera. Grind it without using any water.
Heat a kadhai, add the cooked green gram along with the coconut-chilli-cumin mixture. Add turmeric powder and mix well.
Add some water to adjust consistency. Allow it to simmer on low flame for couple of minutes. Check for salt and add extra if required.
Switch off the flame and prepare for tempering.
In a tempering pan, heat coconut oil, add mustard seeds, whole red chillies and curry leaves. Once mustard crackles, pour the tempering over the curry, mix well and serve as main course or side dish for breakfast.