1. Reconstitute the dried peppers. Add the peppers to a saucepot and cover them with water and bring the heat to a boil, reduce and simmer for about 10 to 15 minutes, or until soft. Strain them and allow them to cool while you measure out the al Pastor sauce ingredients.
2. Make the al Pastor sauce. Add all of the al Pastor sauce ingredients and the slightly cooled peppers to the bowl of a food processor or blender and process until smooth. Pour the sauce through a fine-mesh strainer (placed over a large mixing bowl or casserole dish) to create a smooth cohesive sauce. Add salt to taste (if needed) and set aside while you prep the pork. 
3. Prep the pork. Sprinkle the pork butt slices with salt and freshly cracked black pepper to taste. Add the slices of meat directly to the al Pastor sauce and turn them over to coat each piece of meat well. Marinate the meat for at least four hours (or up to overnight which is always tastier).
4. Cook the pork. Here are 4 good and easy options we recommend (plus one bad option) for cooking al Pastor pork at home:
   • Pan-sear the pork in a preheated cast-iron skillet. Remove excess marinade from the pork (otherwise the meat will stick to the pan when you cook it). Slice the meat and pineapple into thin slices. Heat a couple of tablespoons of oil in a heavy-gauged skillet or wok. Just as it starts to smoke, working in batches, add the pork along with a little onion and pineapple and cook for a total of about 12-15 minutes, tossing occasionally to keep the meat from sticking to the skillet and to allow for even crisping. Remove from the skillet and serve immediately. Repeat with remaining pork, onions, and pineapple. *Do not overcrowd the skillet and do not move the meat after it first hits the pan. Allow the mixture to sear for about 4 minutes on medium-high heat before tossing the meat cooking until golden brown and crispy.
   • Grill the pork. Place the pork steaks, onions, and pineapple slices directly onto a preheated grill and allow them to cook until the meat is crispy and sizzling and the onions and pineapple are caramelized. Remove them from the grill and allow them to rest for 4 to 5 minutes, slice them into thin strips, and serve immediately.
   • Cook the pork in a countertop rotisserie. Stake the meat, pineapples, and onions. Start with a slice of pineapple, add 3 to 4 slices of meat, a layer of onions, more meat, and a slice of pineapple and repeat all of the layers until no meat remains, ending with a slice of pineapple on top. Allow any excess marinade to drip off for about 20 minutes before starting the timer and cooking. Shave the meat off in thin slices and add them directly to a preheated skillet to crisp up even more to your liking and serve immediately.
   • Cook the pork steaks under a preheated broiler. Cut the meat into kebab-sized pieces, alternate the meat, pineapple, and onion slices on metal or (soaked) wooden skewers, and place them onto an aluminum foil-lined baking sheet. Bake the kebabs under a preheated broiler for about 20 minutes rotating them 2 to 4 times while cooking to get even crisping on all sides. Remove from the oven and serve immediately, or remove from the skewers and slice the meat into smaller strips before serving. 
   • Roast the pork in a vertical stack in your oven (NOT RECOMMENDED). Stake the meat, pineapples, and onions. Start with a slice of pineapple, add 3 to 4 slices of meat, a layer of onions, more meat, and a slice of pineapple and repeat all of the layers until no meat remains, ending with a slice of pineapple on top. Get ready for the mountain of al Pastor pork to start leaning like the Tower of Pisa. You can avoid this by making 2 smaller (shorter) stacks and roasting them side-by-side on a sheet pan. However, you will still have to shave the meat and pan-sear it after it roasts. So, although it looks really delicious and fun, it’s not a practical way to cook tacos al Pastor at home in our opinion. Roast in a preheated oven 350°F/180C for 1 1/2 to 2 hours, or until the meat in the middle is cooked through.

    5. Assemble the tacos. Once the meat is cooked through, slice or chop the meat and the pineapple and serve it on warmed tortillas with your choice of toppings.