Heat a skillet, spray it with some oil, and then toast the ingredients (except the coriander), one by one, until they are a couple of shades darker and aromatic. Cool in a plate and transfer to a blender along with the tamarind.
If you are using fresh coconut, toast it to a light brown shade. If you're using coconut milk, add it directly to the blender.
Place all the prepped veggies, including the onion, in a microwave-safe dish, ad 1/4 cup of water, cover loosely and zap for about 10 minutes or until the pumpkin is very tender. Set aside. You can do this on a stove-top as well.
Blend the spices with enough water to make a smooth paste. Set aside.
Spray a saucepan with some oil and add the garlic and asafoetida. Saute, stirring, for 30 seconds to a minute. Don't let the garlic turn dark brown or burn.
Add the curry leaves and stir in. Now add the blended masala and let it come to a boil. Turn down the heat and simmer for five minutes.
Add the cooked vegetables and the cooked tuvar dal. Bring the mixture to a boil and then let it all cook on low heat, about 10 minutes, for the flavors to meld. Add water if the stew is too thick.
Add salt to taste. Serve hot over boiled rice.