Peel the Mango, remove the Seed and then cut the Mango into medium size pieces and keep these pieces aside.
Grind Coconut , Cumin seeds, Shallots/Onion and some water together and keep this paste separately.
Wash the Thuvara Parippu and put it in a cooking vessel/pressure cooker. Also add the Mango pieces, chopped Green Chilli, Turmeric Powder, Red Chilli powder along with required quantity of Salt and Water.
Close the cooking vessel/Pressure Cooker and cook the Thuvara Parippu and Mango pieces properly (after having about 2 - 3 whistles, the stove can be put off and take the vessel out from the stove)
Add the ground Coconut into this cooked Curry and stir it well (and if necessary, change the Curry into a serving plate).
Heat Oil in a Frying pan/Cheenachatti, splutter the Mustard seeds and then add the Curry leaves also and add this Mustard seeds and Curry leaves into the Curry.
Pachha Maanga, Thuvara Parippu (Raw Mango, Red Gram) Curry is ready. This Curry can be served with Cooked Rice/Chappathi/Poori etc.