⁣SPECIAL EQUIPMENT:
Ice-water bath (large bowl filled with ice and cold water)
Spice grinder
In a small cast-iron skillet or heavy-bottom sauté pan, heat 2 teaspoons of lard or fat over high heat until it is almost smoking, then add the chili peppers and reduce the heat to medium. Toast the peppers in the lard until dark red on both sides, about 4 minutes total. Use tongs to transfer the peppers to a small mixing bowl. If you want to dial back the heat, discard some of the seeds from inside the peppers once they are cool enough to handle, then transfer them to the spice grinder and grind into a fine, slightly pasty powder. Set aside.
Place the tripe in a large, heavy-bottom stockpot and add the vinegar. Cover with cold water, bring to a boil, and let boil for 10 minutes. Drain in a colander and shock in the ice-water bath. Clean out the stockpot and set aside.
In a wide, shallow bowl, whisk together the mushroom powder and 2 teaspoons each salt and Szechuan pepper. Toss the pork cubes in this mixture to evenly coat and season.
In the stockpot, heat the remaining 2 tablespoons of lard over high heat. Working in batches to avoid overcrowding the pan, sear the pork on all sides in the hot lard, removing the meat with tongs to a nearby plate as it finishes.
Pour off any excess oil in the bottom of the pan, and over medium heat, add the Szechuan peppercorn oil, fermented black beans, garlic, mushrooms, and reserved ground chili peppers and stir, scraping the bottom of the pan with a wooden spoon to dislodge the browned bits of pork. Cook this mixture for about 5 minutes, or until the moisture from the mushrooms has largely sizzled away, then stir in the doubanjiang, tomato paste, and, if using, MSG and cook, stirring regularly, for 3 to 5 minutes, to let the mixture darken. Deglaze with the beer, continuing to scrape the bottom of the pan. Once the beer has reduced slightly and there is no whiff of alcohol, which should only take a few minutes, stir in 2 cups of the stock and the fish sauce and let the mixture come to a boil. Add the reserved tripe and pork and the accumulated pork juices, and add more stock if necessary to barely cover the meat. Bring to a boil, reduce the heat to a simmer, and cook, stirring occasionally, for 2 to 2½ hours, until the pork and tripe are very tender.
In a clean mixing bowl, whisk together the cornstarch and 2 tablespoons cold water to form a slurry, then add this mixture to the simmering sauce, whisking and stirring well to incorporate it into the sauce and thicken it slightly.
Taste the sauce and adjust the seasoning with additional ground peppercorns, salt, MSG, and peppercorn oil as desired. Serve in a bowl, garnished with pork floss, chives, scallions, and cilantro as desired, and possibly splashed with more peppercorn oil or with more ground peppercorns sprinkled on top, with steamed white rice alongside.
Serves 8