1 whole dried New Mexico, costeño, or choricero chili, seeds and stem removed (see notes above)
1 whole chile ancho or pasilla, seeds and stem removed (see notes above)
1 whole chile negro, seeds and stem removed (see notes above)

1 quart low sodium store-bought or homemade chicken stock
3 tablespoons vegetable or canola oil
2 small onion, finely sliced (I suggest more than 2 onions to leave have enough carmelized onions left over for later!)
6 medium cloves garlic, smashed
2 teaspoons ground cumin
2 teaspoons dried oregano
4 chipotle chilis packed in adobo, roughly chopped, with 2 tablespoons adobo sauce (next time try 2 w/ seeds and 2 w/o seeds)
1/4 cup apple cider vinegar
3lb of Pork Shoulder
Kosher salt and freshly ground black pepper
2 whole bay leaves
Kosher salt

1. Place dried chilies on a microwave-safe plate and microwave on high power in 15-second increments until pliable and toasted-smelling, about 30 seconds total. Transfer to a 2-quart microwave-safe liquid measuring cup or bowl. Add 2 cups chicken broth, cover with plastic wrap, and microwave on high power until gently simmering, about 5 minutes. Remove from microwave and set aside.
Alternative: Adjust oven rack to lower middle position and preheat oven to 275°F. Add dried chiles to large heavy-bottomed Dutch oven or stock pot and cook over medium-high heat, stirring frequently, until slightly darkened with intense, roasted aroma, 2 to 5 minutes. Do not allow to smoke. Remove chiles to small bowl and set aside.

2. At medium heat, add remaining two tablespoons oil and heat along with onions and garlic and cook, stirring frequently, until deep brown and just starting to burn, about 10 minutes. Add cumin/oregano and cook, stirring constantly until fragrant, about 30 seconds. Add chipotle chilis, vinegar, and remaining chicken broth. Scrape up browned bits from bottom of pan, simmer until reduced by about half, then transfer entire contents to the jar of a blender.

3. Add soaked chilis and their liquid to the blender. Start blender on low and slowly increase speed to high. Puree until smooth, about 1 minute. Set aside.

4. Place beef, bay leaves, and sauce into slow cooker for 8 hours on low.

Adapted from http://www.seriouseats.com/recipes/2012/04/tender-beef-barbacoa-chipotle-tacos-recipe.html

Tried different chiles (california, guajillo, new mexico)

Eat with Corn Tacos
Mango Salsa
Red Onions + Cilantro + Lime Juice