Scrub, clean and wash trotters thoroughly and drain. Boil the trotters in sufficient water with one fourth teaspoon turmeric powder, salt.
Blanch the trotters over rapid heat for five minutes, remove and wash. This will remove the dirt from the trotters. Peel and wash sambar onions.
Wash and roughly chop tomatoes. Peel and chop ginger and garlic together roughly.
Remove stems, wash and slit green chillies. Clean, wash and finely chop coriander and curry leaves.
Grind scraped coconut in one-cup warm water, squeeze and extract thick coconut milk and reserve.
Dry roast masala items and pound to a coarse powder Heat oil in a vessel add star anise, bay leaves, cinnamon and fry till the flavor is released.
Add the trotters and sauté till light brown. Add ginger, garlic, sambar onions, green chillies and curry leaves.
Keep stirring. Sprinkle the masala powder, remaining turmeric powder and asafoetida and continue cooking.
Add the chopped tomatoes, chopped fresh coriander, salt and about two liters water. Bring to a boil, reduce heat and simmer for at least four to six hours.
The soup quantity should have reduced by half by now. Remove the trotters carefully and keep aside.
Strain the soup, pressing the residue to extract all the flavors.
Reheat the soup, add coconut milk, check seasoning and serve piping hot poured over the trotters with a lemon wedge.