Cut open the snake gourds along the length and run your fingers along the pith to clear off the insides. Place the gourds bunched together and slice them into pieces of 1 cm thickness or so.
Grind the roasted spices along with coconut and 3 tbsp water to a fine paste.
In a deep pan, place the gourd slices, water with pinch of turmeric. Bring the water to a boil and let it simmer until the gourd is tender (for about 5-8 minutes). Keep a watch so that gourd slices are not mashed.
Once the vegetable is cooked, add the finely ground coconut-spice paste, 3/4 tsp of salt and let the gravy simmer for 2 minutes. Add a little water if the gravy gets too thick while simmering.
In a small pan, heat a tsp of oil, and put in the mustard seeds. Once it splutters, add the udad dal, saute till golden and lastly throw in the curry leaves. Transfer the tempered oil to the gourd in coconut gravy.