Grill the liver slices quickly on both sides.
Cut the liver and caul fat into pieces and put in a bowl with the spices and salt. Cover with clingfilm and place in the refrigerator for 1 hour.
Thread the liver onto 6 skewers, alternating with two pieces of fat on each skewer, and cook for 8 minutes, turning regularly, over hot coals or under a hot grill.
Serve with chipped potatoes.