3 tbsp. canola or corn oil
4 lb. boneless pork shoulder, cut into 3 equal pieces
1 yellow onion, finely chopped
3/4 c. cider vinegar
3/4 c. tomato ketchup
1/3 c. firmly packed brown sugar
1/4 c. light molasses
2 tsp. red pepper flakes
1 tbsp. Worcestershire sauce
1 tsp. dry mustard
1 tsp. salt
1 tsp. freshly ground pepper
Soft sandwich rolls, split and toasted for serving
Brown the pork:
In a large fry pan over medium-high heat, warm the oil. Add the pork pieces and brown well on all sides, about 12 minutes total. Transfer the pork to a slow cooker.
Make the sauce and cook the pork:
Pour off all but about 1 tbsp. of the fat from the fry pan and return the pan to medium0high heat. Add the onion and saute until golden, about 5 minutes.
Add the vinegar and deglaze the pan, stirring to scrape up the browned bits from the pan bottom. Stir in the ketchup, brown sugar, molasses, red pepper flakes, Worcestershire sauce, mustard, salt and pepper.
Cook,, stirring occasionally, just until the mixture begins to bubble. Pour over the pork. Cover and cook according to the manufacturer's instructions until the pork is very tender, 4-5 hours on high or 6 -10 hours on low.
Shred the pork and serve:
Transfer the pork pieces to a platter. Using a pair of forks, shred each piece of pork, removing and discarding any large pieces of fat. Skim the excess fat off the sauce and stir to combine. Serve the pork and sauce atop the sandwich rolls.