How to Make It
In a mortar, coarsely crush the peppercorns. Add the cilantro roots, garlic clove and salt and pound to a paste. Scrape the paste into a large nonreactive bowl. Add the chicken livers and toss to coat. Stir in the fish sauce and soy sauce, cover and refrigerate for 30 minutes.
Light a grill. Thread the chicken livers onto four 10-inch metal skewers, leaving a bit of space between them. Grill the livers over moderate heat, turning once, until charred outside and still slightly pink within, about 4 minutes. Serve right away.
Cilantro root is available at Asian supermarkets.