Make the marinade. Place the garlic in a small microwaveable dish, cover with water and microwave for 1 minute. Drain and separate 6 out for the salsa. Place the remaining 8 in a blender jar. Add the ancho powder along with the spices and herb, vinegar, 1 ¼ cups boiling water and 1 ½ teaspoon salt. Blend until smooth. Measure out 1/3 cup. Scrape the remainder into a container with a tight-fitting lid and refrigerate for another use. Scrape the 1/3 cup of the marinade back into the blender jar. Break up the achiote into the blender and add the oil and 1/3 cup water. Blend until smooth.
Marinate the meat. If you have pork tenderloin, use a sharp knife to cut down the center from end to end. (You can stop just before cutting through, let the two halves fall away from each other and you’ll have a single piece of butterflied pork tenderloin.) No matter what cut of pork you have, use a heavy mallet or back of a heavy pan to pound it into about half its thickness—this will ensure tenderness. Lay it in a 13X9 inch glass or stainless steel baking dish. Smear or brush marinade over both sides of each slice of pork—I like more than just a light coating. Refrigerate any unused marinade for another round of taco making. If time allows, cover and refrigerate the meat for a couple of hours for the flavors to penetrate.
Make the salsa and sauce. Toast the chiles in an ungreased skillet over medium heat, turning them for a minute or so until they are aromatic and toasting smelling. Scoop into a small bowl, cover with hot tap water, weight with a plate and soak for about 20 minutes. Lay a piece of foil in the same skillet, lay in the tomatillos cut side down, then set over medium heat. Roast until blotchy black underneath, 3 or 4 minutes, then turn them over and roast the other side. Scoop into a clean blender jar along with the reserved garlic. Drain the chiles and add them too. Blend to a coarse puree. Add enough water to give the salsa an easily spoonable consistency, then taste and season with salt, usually a scant teaspoon. A little sugar can help to bring out the chiles’ natural fruitiness. Pour about 2/3 of the salsa into a serving dish. Pour the remainder into a small saucepan and add the orange juice and chicken broth. Simmer over medium heat for 5 minutes or so, until slightly reduced. Taste and add a little more salt (you’ll probably need about ½ teaspoon) and sugar if you think the sauce needs it. Keep warm on low heat or on the side of the grill.
Grilling and serving. Heat a gas grill on medium-high to high or light a charcoal fire and let it burn until the coals are covered with gray ash and quite hot. Brush or spray the sliced or knob onions and pineapple with oil. Grill, turning regularly for several minutes, until they are richly colored and softening—you want them to still have nice texture. Chop the onions and the tender pineapple into small pieces. Keep warm on the side of the grill.
Grill the meat on the very hot grill, cooking it only on one side to duplicate the delicious crusty char every one associates with tacos al pastor. (I like to cover the grill for a couple of minutes to ensure even heat top and bottom.) When the meat is cooked—which will take 2 to 4 minutes (depending on the meat’s thickness and the fire’s heat), cut it into thin slices. Serve with the onion and pineapple: I find it easiest to mix the meat together with the onion and pineapple, scoop a portion of the mixture into a warm tortilla, splash on a little of the warm sauce, then top with a spoonful of morita chile salsa and a sprinkling of cilantro. Serve with a lime wedge for each person to squeeze onto their taco. I think tacos al pastor aficionados will be happy.
A very unconventional cauliflower tacos al pastor: Core a medium (1 ¾- to 2-pound) cauliflower and cut the florets into pieces that are less than 1 inch. (If you buy florets, you’ll need 1 ¼ pounds, but you’ll probably need to cut them smaller.) Toss with 2 tablespoons of the marinade and 1 tablespoon vegetable or olive oil. Sprinkle with salt. Roast on a rimmed baking sheet in a 425-degree oven or grill on a perforated grill pan over a medium-hot fire until tender (about 30 minutes) Serve with the sauce, salsa, pineapple, onions—the whole 9 yards. Guests at our basement mezcal bar Bar Sótano love these.