Roast the bones in the oven for 20 mins on 180°C.
Let the bones cool, and then scrape the meat out.
Add all the ingredients into a bowl and thoroughly mix together until smooth.
Place on a piece of cling wrap that is layered down flat on the counter.
Roll the softened (not melted) butter into a sausage shape and put in the freezer to set for an hour, then remove from the freezer and transfer to the fridge.
Use as needed by just cutting a slice off the roll.
Recipe reprinted with the permission of Charango Barbacoa.