Crockpot pork shoulder

Name: Crockpot pork shoulder
Cuisine: American
Ingredients: 3–4 lb pork shoulder (Boston butt); 2 apples, sliced (Honeycrisp or Granny Smith); ¾–1 cup chicken stock; 2–3 tbsp brown sugar (optional); 1 tbsp Worcestershire sauce; 1 tbsp apple cider vinegar; Your favorite pork rub; Pork rub; 2 tbsp brown sugar; 1 tbsp paprika; 2 tsp garlic powder; 2 tsp onion powder; 1 tsp salt; 1 tsp black pepper; ½ tsp cumin; ½ tsp chili powder