Immerse the pig’s trotter and the peas in cold water in a pan, bring to the boil and skim. Put in the bayleaf and the seasoning, cover and cook slowly for an hour. In another pan simmer in butter the chopped onion, the diced potatoes, the leeks chopped fine, till they soften. Then transfer from the other pot the cooked peas and their liquor, by now more or less a purée, and simmer together for 20 minutes. What meat you can find on the trotter can be cut up small and put into the soup.
Sprinkle with the chopped parsley or coriander leaves and serve with little croûtons fried in pure pork fat. The soup should be dense.