"Traditionally a Sunday morning treat, but barbacoa is great any morning. Barbacoa can be for the more adventurous, but a real treat none the less. I do not recommed substituting the cheek meat with roast, it won't taste right. Barbacoa has a certain gelatinous slide and tack that is the hallmark of the genre."
Wash off cheek meat and do not discard fat. Coat with olive oil and rub in dry ingredients, this recipe calls for alot of salt, but is needed. Wrap and refrigerate 4 hours to overnight. Pour 2 cups of water into slow cooker. Take cheek meat, onion, and garlic and double wrap in tin foil and seal tight. Turn slow cooker on to low and let cook 7 to 8 hours checking water levels every so often. After slow cooking take out and drain most of the liquid. Shred with two forks and serve on tortillas with hot sauce and chopped cilantro.