Marinated Pork Sandwich de Chile

By Shelley Wiseman: A cemita is an oversized, sweet, sesame seed bun.
For chile-marinated pork:6 dried guajillo chiles* (1 1/2 oz)
1 dried ancho chile* (1/2 oz)
4 thin (1/2-inch) rib pork chops (1 lb total), bones discarded
1/2 teaspoon cumin seeds
1/4 teaspoon black peppercorns
1 whole clove
1 (1/2- by 1/4-inch) piece cinnamon stick
2 tablespoons cider vinegar
2 large garlic cloves, quartered
1 tablespoon dried oregano (preferably Mexican), crumbled
1 teaspoon salt
2 to 3 tablespoons vegetable oil
For sandwiches:
4 Mexican cemita rolls* or 8 sesame seed hamburger buns
2 ripe California avocados
1/2 cup fresh papalo leaves* or cilantro leaves
6 oz Oaxacan string cheese* or other string cheese, finely shredded (1 1/2 cups)
4 canned chipotle chiles in adobo (optional), finely chopped
1/2 large white onion, thinly sliced
1 large plum tomato, thinly sliced crosswise
Prepare chiles and pork:•Discard chile stems/seed/ribs & cut guajillo & gancho chiles open lengthwise w/shears.

•Heat a dry 10- to 12-inch heavy skillet or griddle over moderate heat until hot, then toast chiles, a few at a time, turning and pressing down with tongs, about 10 seconds each side
•Transfer chiles to a bowl, cover with hot water & soak until softened, about 20 minutes.
Flatten pork while chiles soak:
•Trim fat & sinews from pork & pound between 2 sheets of wax paper with flat side of a meat pounder or with a rolling pin until meat is about 1/8 inch thick.
Marinate pork:
•Heat skillet over low heat until hot then toast cumin, peppercorns, clove, and cinnamon, stirring constantly, until fragrant and cumin is a shade darker, about 1 minute. Transfer hot spices to a blender and add vinegar, garlic, oregano, salt, and soaked chiles with about 1/3 cup soaking water, then blend until smooth. Transfer half of chile paste to an airtight container and chill or freeze for another use, then put remainder in a small bowl.
•Spread a thin layer of chile paste in middle of a sheet of plastic wrap large enough to wrap all of meat and put 1 pork chop over paste. Spread a thin layer of chile paste on top, then continue layering meat, spreading each piece with chile paste. Wrap stacked pork in plastic wrap and marinate, chilled, at least 2 hours.
Cook pork and assemble sandwiches:•Heat 1 1/2 tablespoons oil in a 12-inch heavy skillet over moderately high heat until hot but not smoking. Season pork chops with salt and sauté, in batches, adding more oil as necessary, until just cooked through, 1 to 2 minutes per side. Transfer chops as cooked to a sheet of foil and keep warm wrapped in foil.
•Preheat broiler. Cut rolls in half horizontally and arrange, cut sides up, on a large baking sheet. Broil buns about 6 inches from heat until golden, about 1 minute.
•Halve, pit, and lightly mash avocados in peel with a fork, then spread thickly on cut sides of rolls. Season avocado with salt, then top with papalo. Make sandwiches with pork, cheese, chipotles (if using), onion, and tomato, pressing sandwiches together. Cooks’ notes: Pork can be marinated up to 2 days. *Available at Latino and Mexican markets.