Slow Cooker Tacos al Pastor

Step 1
Place pineapple, onion, chipotle peppers plus 1 1/2 teaspoons adobo sauce, guajillo chiles, chile de arbol, garlic, and oregano in a food processor. Blend until smooth. Transfer to a bowl and add orange juice, vinegar, achiote powder, salt, cumin, lime zest, chile powder, and black pepper. Mix sauce well.

Step 2
Place pork in a slow cooker and cover with the sauce. Cover and cook on Low until pork is very tender, 7 to 9 hours. Begin heating tortillas 35 to 40 minutes before pork is done.

Step 3
Heat oil in a saucepan over high heat. Cook tortillas one at a time until brown spots appear, 30 seconds to 1 minute per side. Plate tortillas in stacks of two for each taco.

Step 4
Shred pork using 2 forks; mix to coat with the sauce. Scoop pork onto tacos using a slotted spoon. Top each with a portion of pineapple, cilantro, and onion.