In a large mixing bowl, combine the olive oil and apple cider vinegar.
Add the brown sugar, smoked paprika, coarse kosher salt, ground black pepper, garlic powder, onion powder, ground cumin, dried mustard powder, and cayenne pepper to the wet mixture. Whisk until all ingredients are thoroughly combined and a smooth paste forms.
Apply the wet rub generously to the pork shoulder, massaging it into the meat to create a thick, even coating. Make sure to cover all the nooks and crannies of the pork.
Wrap the seasoned pork shoulder tightly in plastic wrap and refrigerate for at least 4 hours or preferably overnight. This allows the flavors of the wet rub to penetrate the meat, ensuring a deep, rich flavor.
Follow your preferred cooking method (slow cooker, smoker, etc.) to cook the pork shoulder until tender and easily shredded.
Unwrap the cooked pork, let it rest, and then shred using two forks or your preferred shredding tool. Serve with your favorite barbecue sauce and enjoy the taste of a true champion pitmaster's pulled pork.