Put all the meats through a mincer, then mixed together in a bowl. You can use a food processor, but it is essential that the blade has been sharpened and only pulse-chop very small quantities of each meat at a time.
Grind the fennel seeds and about half of the peppercorns in a mortar. Add to the meat mixture, along with some salt and the remaining peppercorns. Mix well, then stuff into