Coles Boneless Pork Shoulder Roast. The boneless shoulder roast is not too dissimilar to the leg roast but has slightly more marbling. Easy to carve and makes a great value choice roast for any occasion. For best results to achieve a crunchy crackling remove all the packaging and allow the roast to dry out uncovered in the fridge overnight. Rub with oil and season generously with salt and be sure to cook in a hot oven, 240C for at least 45 minutes. Once you have achieved the crackling, reduce the oven temperature and continue to cook for 25 minutes per 500g. Don't forget to rest the roast for at least 15 minutes before carving.