Remove the stem and seeds from the chiles and place the guajillo chiles in a dry skillet and toast them over medium-high for 2-3 minutes per side. Add about ½ cup of water to the bottom of the skillet and simmer the chilies for 3-4 minutes until they are softened. Add the hydrated chiles to the blender.

Add half a yellow onion, garlic cloves, pineapple and orange juice, cider vinegar, achiote paste, ground cumin, brown sugar, chipotle powder, dried oregano and salt to the blender and blend until thick and smooth.

Place the chicken thighs in a zipper-top plastic bag or non-reactive (like glass) dish and cover with the marinade from the blender and toss to coat well.

Marinate the chicken for 8 hours but not more than about 14 hours or the acidity in the pineapple juice will change the texture of the chicken.

Add a hardwood blend of pellets to the hopper and fire up your Traeger smoker or other smoker. Set it to 180-F.

Remove the top of the pineapple and set it aside to use as a garnish or decoration when serving.

Remove the outer layer of the pineapple and cut 3 1.5-inch thick slices of pineapple. Reserve the rest of the pineapple for nibbling on later.

Add one slice of pineapple to the bottom of the vertical skewer, then load on half the chicken thighs, alternating the direction of them so that they aren't evenly overlapping each other. This is what gives you such tasty caramelized outer bits.

Top the chicken with another slice of pineapple, and add the rest of the chicken, and finish with the final slice of pineapple.

Smoke the chicken at 180-F for about an hour to give it a good dose of smoke.

Turn the smoker up to 300-F and finish cooking the al pastor until it reaches 165-F with a digital meat thermometer. It should take about 2 hours, but actual cooking time will depend - see notes below.

Slice the meat right off the skewer and add it to your tacos, nachos, burritos and more. Or, just eat it like it is!