Prepare the Pork & Sauce:Place the sliced onions, garlic, and chillies in a large ovenproof dish or Dutch oven. Lay the pork shoulder on top.In a bowl, whisk together the cider, both mustards, vinegar, honey, smoked paprika, cumin, salt, and pepper. Pour the mixture over the pork, ensuring it coats the entire surface. Gently rub it in, making sure to work it into every crevice for maximum flavor. Cook Low & Slow:Cover with a lid or tightly wrap with foil.Bake at 160°C (300°F) for 4-5 hours, or until the pork is tender and easily pulls apart with a fork. Shred & Serve:Remove the pork from the pot and shred with two forks.Mix some of the cooking liquid into the meat to keep it juicy.