Place the salt, sugar, New Mexican chile powder, granulated onion, smoked paprika, Spanish paprika, coriander, cumin, juniper, pepper, savory, cayenne, celery seed and chipotle in bowl and mix until well combined.
Place the pork butt into a deep half hotel pan with the onions and garlic. Rub the pork butt with 1 cup of the spice mixture and mix with the onions and garlic. Cover the pan with plastic wrap and rest overnight in the refrigerator.
Preheat the oven to 350 degrees F.
Fill the pan two-thirds with water and then cover with a layer of parchment and then a layer of foil. Slow roast the pork butt until fork tender, 7 to 8 hours.
Cool the pork to handle and then shred the meat.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.