Cook it the traditional way; a southwestern rub will defiantly enhance the flavor. But any rub with cumin and chili will work. I prefer ground Ancho chili (it gives it more authentic taste).
Once it’s done and shreded, that’s when you will flavor it. This is what I use:
6-8 dry whole Ancho chili peppers
1 tsp cumin
¼ cup of limejuice
¼ cup cider vinegar
½ cup chopped cilantro (fresh)
1 small can of Chipotle (smoked Jalapeno peppers)- this is optional, chipotle peppers are usually spicy hot. Adjust based on your preference.
3 cloves of garlic-minced
½ red onion- minced
½ cup bell pepper or peblano pepper- chopped
¼ tsp brown sugar
3 tbs olive oil
Salt and pepper to taste.
Seed and stem the chili peppers and soak them in warm water overnight. Drain the peppers and place them in a stockpot. Cover the peppers with water and bring to slow simmer until soft. Drain the peppers and place them in a blender or food processor with the vinegar, lime juice, cumin, cilantro, chipotle(if using), and brown sugar. Process the mixture until smooth. If you like smoother sauce, you can strain it. If you prefer the sauce a little thinner, add some of the water you used to boil the peppers.
In a saucepan, place the olive oil and sauté the onions, bell peppers, and garlic until soft. Add the pepper mixture and stir until warm. Adjust seasoning to taste.
Once the pork is ready and pulled, pour the chili mixture on it and keep it warm. Allow time for the pork to absorb the flavor from the sauce.
You can also place the pork (prior to shredding) in a foil pan and pour the chili mixture over it. Cover the pan and return the pork to the smoker, and let it brew in the sauce for about an hour. This option will give you a stronger flavor and makes the pork easy to shred. Return the meat to the sauce after shredding.
I hope this help.