1. Pre-heat the oven to 170 °C. Use a blowtorch to burn any hair from the skin of the pig and cut down the middle, from nose to tail, with a sharp knife, so that the head and tail are still intact (you may want to ask your butcher to do this).
2. Open the pig out like a book and rub rock salt all over the skin on both halves of the pig. Place it, skin-side down, on an oiled oven rack. Mix the sliced potatoes and onion with the garlic, bay leaves, fresh thyme and salt and pepper and tip into a large roasting tin.
3. Pour over enough olive oil to come halfway up the potatoes and then slide the dish into the oven, positioned underneath the rack with the suckling pig on.
4. After 1 hour turn the pig halves over and pierce the skin with a fork. Use a large spoon to turn the potatoes.
5. Continue to roast for another 1 1/4 hours, turning the potatoes once again, and then put the glaze over the pig. Cook for another 15 minutes until the meat is tender, the skin is golden and the potatoes are cooked. Drain the potatoes from the oil and serve with a good piece of suckling pig.