Heat a dry skillet over medium heat and toast the ancho and pasilla chiles for about 5 minutes, stirring occasionally, until fragrant—this deepens their flavor significantly. Transfer to a bowl and cover with the chicken stock to soften for 10 minutes while you prepare the aromatics. In the same skillet, heat the vegetable oil over medium heat and toast the cumin, oregano, and achiote powder for 30 seconds until fragrant, then add the chipotles in adobo and their sauce and cook for another 30 seconds. Remove from heat and add the vinegar, orange juice, salt, and sugar, then stir in the minced garlic. Pour this mixture into a blender with the softened chiles and their soaking liquid, and blend until completely smooth—about 1 minute—creating your marinade base.

Working with the thin pork sirloin slices, place them between plastic wrap or parchment paper and gently pound them to about 1/4-inch thickness using a meat mallet—this ensures even cooking and helps them absorb the marinade. Transfer the pounded pork to a large bowl and pour the marinade from Step 1 over it, stirring well to coat every piece evenly. Cover and refrigerate for at least 2 hours, or ideally overnight, to allow the flavors to penetrate the meat deeply.

Preheat your oven to 275°F. In a loaf pan or small baking dish (roughly 9x5 inches), begin layering by arranging a thin layer of thinly sliced bacon on the bottom, then add a layer of marinated pork, overlapping slightly. Continue alternating bacon and pork layers until all ingredients are used, finishing with a bacon layer on top. I like to reserve a tablespoon or two of the excess marinade to pour over the top—it keeps the meat moist during the long bake. Cover the pan with foil and bake at 275°F for 4 hours, allowing the pork to become incredibly tender and the flavors to meld beautifully.

Remove the baked meat from the oven and let it cool to room temperature, then refrigerate for at least 2 hours (this makes slicing much easier). While the meat chills, increase the oven temperature to 350°F and prepare the pineapple: brush the 1/2-inch thick pineapple rings generously with the rendered fat from the top of the cooled meat stack. Arrange the brushed pineapple on a baking sheet and bake for 25 minutes until caramelized and golden at the edges. Once cooled slightly, chop the pineapple into bite-sized pieces.

Remove the chilled meat stack from the pan and slice it into thin shavings—you'll get beautiful, tender pieces. Heat a large skillet over medium-high heat and add about 1 tablespoon of the rendered fat from the meat stack. Working in batches to avoid crowding, add the meat shavings and cook until the edges become crispy and browned, about 3-4 minutes. Once crisped, add the meat juices from the bottom of the pan (or any remaining marinade) and cook for another minute until everything is glossy and glazed. This technique builds incredible depth of flavor with caramelized edges while keeping the interior tender.

While the meat finishes crisping, warm the corn tortillas in a dry skillet or directly over a gas flame for about 30 seconds per side until pliable. In a small bowl, combine the finely diced white onion with the chopped cilantro and toss with the 1/2 teaspoon of kosher salt—this simple mix becomes an essential textural and fresh contrast to the rich meat. Arrange all your taco components on the table: warm tortillas, crispy al pastor meat from Step 5, chopped pineapple from Step 4, the onion-cilantro mix, salsa verde, and lime wedges.

To build each taco, place a small handful of the crispy meat on a warm tortilla, add a small spoonful of chopped pineapple, a pinch of the onion-cilantro mixture, and a small dollop of salsa verde. Finish with a squeeze of fresh lime juice. Serve immediately while the meat is still warm and the tortillas are soft—the contrast of textures and flavors is what makes tacos al pastor truly special.