Clean 3 hazel grouse, fry in ⅛ lb butter, and cool. Remove the meat from the bones and chop and pound the meat. Add nutmeg, (⅛ lb grated Parmesan for those who like it,) 3–4 spoons chopped truffles, and ⅛ lb butter. Rub all this through a fine sieve, mix until it thickens, and transfer to a butter dish. To keep this butter for a long time, pack it in a stoneware bowl and pour on melted beef fat.