Yield: 8 servings.
1 (6-pound) boneless pork shoulder
Salt and pepper
1 onion, chopped
1 cup water
1 cup apple cider vinegar
1 (5-ounce) bottle liquid smoke, mesquite, or hickory
½ cup soy sauce
1 cup light brown sugar
Red pepper flakes
Trim pork of any excess fat. Sprinkle salt and pepper liberally on all sides of pork. Place in a large Ziploc bag and refrigerate overnight. Scatter onion over bottom of slow cooker and place pork on top. Add water, vinegar, and liquid smoke. Cover and cook on low until very tender, about 8 to 10 hours. Remove meat and let cool.
When cool enough to handle, pull meat into thin shreds, removing all fat and gristle. Skim excess fat from liquid in slow cooker.
Return pulled pork to slow cooker, and stir in soy sauce and sugar. Season with salt and red pepper flakes, if needed. Cook for an additional hour on low.