This is a one-pot dish. Every element of the soup gets added to the one pot so the flavors can be built over time. Finely chop the leeks, carrots and celery and cook them down in a large pot with a little bit of olive oil and the salt. Shred the potato with a cheese grater into the pot as well and stir in with some of the butter
Finely dice the lamb meat; add it to the soup pot and stir well so the lamb fat starts to cook off into the vegetables. Add the madras curry powder and stir well. Cube the remaining butter, add it to the pot and fold it in well.
Once the butter is fully melted down, add the cream and coconut milk and stir the soup base very well again. Let the soup base simmer on low heat for 2 to 3 hours, and then add the clams. If you add them too soon, they will over-cook and get chewy. Allow the clams to cook for 10 to 15 minutes, and then move the pot off the heat but continue to stir thoroughly. Garnish with some fresh parsley, carrot leaves and a light dusting of madras curry powder. Serve with oyster crackers or rustic bread.