Al Pastor Achiote-Guajillo Marinade

Heat a dry comal or cast-iron skillet over medium-high heat until very hot. Press each guajillo and ancho chile flat on the dry surface with a spatula for 10 to 15 seconds per side — you want the flesh to darken from bright brick-red to a deeper reddish-brown with small blistered spots, releasing a bloom of sweet, slightly smoky aroma. Guajillo chiles toast faster than anchos — watch them carefully. The moment you smell something fruity and slightly toasty, they are done. Transfer immediately to a bowl and cover with 2 cups of very hot (not boiling) water. Weigh them down with a plate and soak for 20 to 25 minutes until completely soft and pliable. The soaking water turns a vivid brick-orange. Reserve 3 tablespoons of the soaking liquid — it carries flavor that will be added to the marinade. Drain the chiles and use immediately.

Combine the drained soaked chiles, reserved chile soaking liquid, achiote paste, onion, garlic, fresh pineapple, white vinegar, orange juice, toasted cumin seeds, dried oregano, black peppercorns, ground cloves, and salt in a blender. Blend on high for 2 full minutes until the marinade is completely smooth. Stop the blender and rub a small amount between your fingers — if you feel any graininess from the seeds, peppercorns, or chile skins, blend for another minute. The finished marinade should be vivid orange-red to deep brick-red, completely smooth, and will stain anything it touches. Taste it now: the raw marinade will be quite sharp — bright from the pineapple and vinegar, with a building chile heat and an earthy, almost floral depth from the achiote. It will mellow considerably during the marinating period, losing its rawness and integrating into the meat. Use immediately: apply to thinly sliced pork shoulder (3 to 5 mm slices), coating every surface generously. Marinate refrigerated for at least 4 hours, ideally 12 to 24 hours.