Pound the carcass with a mallet and/or chop it with a cleaver. Add it to the container of a food processor. Add the butter. Blend well.
Scrape the mixture into a saucepan. Cook, stirring, until a nice nutty smell comes from the saucepan. Add water to cover to a depth of about 1 inch over the top of the butter mixture. Bring to the boil and remove from heat.