Trim excess fat from the pork shoulder (leave some fat for flavor). Cut the meat into 3-4 inch chunks to ensure even cooking. Season generously with salt and pepper on all sides.

Heat vegetable oil in a large skillet over medium-high heat. Working in batches, sear the pork chunks until golden brown on all sides, about 2-3 minutes per side.

Place sliced onions in the bottom of your slow cooker. Add minced garlic on top.

In a medium bowl, whisk together chicken broth, barbecue sauce, apple cider vinegar, brown sugar, Worcestershire sauce, paprika, mustard powder, cayenne pepper, salt, and black pepper until well combined.

Transfer the seared pork chunks to the slow cooker, nestling them among the onions. Pour the BBQ sauce mixture over the meat, ensuring it's well coated.

Cover and cook on LOW for 8-10 hours or on HIGH for 4-5 hours, until the pork is extremely tender and easily shreds with a fork.

Once cooked, carefully remove the pork chunks to a large cutting board or bowl. Using two forks, shred the meat, removing any remaining fat pieces.

For a thicker sauce, strain the cooking liquid into a saucepan, discarding the onions or keeping them based on preference. Simmer the liquid over medium heat for 10-15 minutes until reduced and slightly thickened.

Return the shredded pork to the slow cooker and mix with the cooking liquid (or the reduced sauce). Keep on WARM setting for 20-30 minutes to allow the flavors to meld.

Toast hamburger buns if desired. Pile the pulled pork high on buns and top with extra barbecue sauce, coleslaw, and pickles if using.