2 pounds pork back fat, sliced into thin, 1-inch-wide strips, 8 to 10 inches long, or 1 piece caul fat, about 8 by 20 inches
Heat oven to 325°. To make the forcemeat, spread the peppercorns, cumin, and allspice on a baking sheet and toast for 3 to 5 minutes, until fragrant. Let cool completely, then transfer to a spice grinder, add the bay leaf, and grind finely.
Place the lamb and fat in a large, nonreactive bowl. To make the spice kit, in a small bowl combine the freshly ground spices, sea salt, curing salt, Aleppo pepper, and garlic and mix well. Mix the spice kit with the meat, cover, and refrigerate overnight.