Take all the 3 dals together in a bowl, wash it once with water. Add fresh water and soak them for 30 minutes. Drain the dal and keep aside until use.
Heat a tsp of oil in a pressure cooker, add the tomatoes, chili, turmeric powder. Add the drained dal, 3 cups of water and mix.
Add turmeric powder, salt to the dal and mix. Add the freshly grated coconut to the dal. The original recipe doesn't use fresh coconut, but i like to add coconut to my dal recipes.
Close the pressure cooker and cook for 4-5 whistles. Let the pressure fall on its own.
Heat a small tadka pan with oil. Add curry leaves, red chilies, chopped garlic and ginger. i didn't have fresh ginger in hand, so omitted it. When the garlic turns brown, add mustard seeds, let it splutter and finally add cumin seeds, take it off the stove and add the sizzling tadka to the dal.
Garnish the dal with fresh coriander leaves. Serve it warm with rice/roti.