In a food processor add oniion, garlic and ginger and add two table spoon of water and make a mixture.
Grind all the other spices except red chilli and turmeric in a grinder and set aside.
In a pressure cooker add oil and heat it till the oil is real hot, add the paaya's to the pot and fry the mutton trotters in the oil by adding the mixture of onion, ginger and garlic.  Cook down the water from onion paste and add turmeric and red chilli powder and salt.
Cook for another 3 minutes add some water and cook down the water.  Add all the grounded spices and cook for 3 minutes.  Add 4 table spoon of water and cook it down. You can repeat the process if you feel that the spices have not been cooked.  This can be checked by smelling the cooked mixture.
Add yogurt and cook it down again, once the oil seperates the dish is ready for the next step of adding 6 cups of water.  Let the pot boil, cover the pressure cooker and let the pressure build.  As soon as the pressure builds, bring the heat to medium and let the dish cook for 60 mintues.

After 60 minutes the dish is ready, garnish with some lemon juice, thinly sliced ginger and cilantro. Eat with Naan on the side.  Enjoy.