2 teaspoons sambal oelek or other Asian chile sauce
4 1/4 pounds boneless pork shoulder, trimmed and cut into 4 pieces
Kosher salt and freshly ground pepper
In a medium bowl, mix the onion with the ketchup, brown sugar, cider vinegar, molasses, mustard and sambal oelek. In a slow cooker, cover the pork with the ketchup mixture. Cook on high until the pork is very tender, about 6 hours.
Transfer the pork to a work surface and, using 2 forks, shred the meat.
Pour the sauce into a large saucepan and bring to a boil. Cook over high heat until thickened, about 15 minutes. Stir the shredded pork into the sauce, season with salt and pepper and serve.
The pulled pork can be refrigerated for up to 4 days.