1. Pat dry pork with absorbent kitchen paper. Place on a rack over a tray. Refrigerate, uncovered for 4 hours or overnight (see Tip).
2. Next day, rub combined salt and oil over pork, making sure it penetrates scores in rind. Place on a roasting rack in a large roasting pan.
3. Cook in a very hot oven (240C) for 25 minutes, or until rind has blistered. Reduce heat to moderate (180C). Cook for a further 1 hour, 30 minutes, or until pork juices run clear when tested with a skewer. Remove. Rest pork, uncovered, for 10 minutes. Remove kitchen string.
4. Meanwhile, to make sauce, heat a lightly oiled medium saucepan over a medium heat. Add onion. Cook, stirring, for 4 to 5 minutes, or until lightly golden. Stir in stock, jam, mustard, vinegar and soy sauce. Bring to boil. Gently boil for a further 15 to 20 minutes, or until thickened slightly. Remove. Stir in thyme. Season with pepper.
5. Transfer pork to a serving plate with roasted vegetables. Garnish with thyme. Serve sliced with sauce.
Tip: Most pork loin roasts are sold pre-scored. If not, ask your butcher to score it for you to save time. Refrigerating pork overnight in the fridge will allow the rind to dry out to help give the best crackling.
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