The rotisserie is vertically set and a hot flame sears and cooks the pork as it slowly rotates. Set atop of the rotisserie is pineapple, the heat of the flames releases the juices of the pineapple and it leaks down onto the pork flavoring it with its sweet taste. The taquero, the guy who makes the tacos, thinly shaves the pork from the spit and into his tortilla-covered palm, cilantro and onions are added and you have Taco al Pastor.
These types of taquerias are found all over the states of Mexico and in the US as well. The recipe for al Pastor has been a kept secret. Chefs do not share it, the recipe remains in the family. You can find versions on the internet and all have different seasonings etc...In its most basic form, al Pastor is pork, pineapple, and dried peppers.
This particular recipe, coming from a grilling expert Steven Raichlen and his book Planet Barbecue, and from a fantastic blog Denver on a Spit: Tacos al Pastor at Home, I've tried several times and is without a doubt, the best taco al pastors I've had. I haven't been to Mexico City or any other Mexican state so I am no expert, but my taste buds aren't lying to me, this is some good sh*t!
Most people, if not all home cooks, don't have space or the daily need for a vertical, flaming spit. Raichlen suggested grilling the pork and pineapple on a hot grill. But first, you need to marinade that pork. You'll need:
3lb pork loin
4 ounces guajillo chiles, seeded, deveined, soaked in hot water for 1 hour
1 cup of chile-soaking liquid
1/4 cup white vinegar
2 garlic cloves
2 bay leaves
1 tablespoon salt
2 teaspoons black pepper
2 tablespoons dried oregano
1 teaspoon cumin
1 teaspoon anise
1 teaspoon dried thyme
After the chiles are done soaking, chop and add to a blender with all other ingredients. Blend until smooth. After a few runs on this recipe, I cut back on the chile liquid to a half cup. I wanted more of a paste texture instead of a watery texture.