Preheat the oven to 150°C. Whisk all marinade ingredients together in a bowl and set aside. Carefully remove skin from ham and score the fat into diamond shapes using a criss-cross pattern. Try not to cut into the meat. Into each little diamond, insert one clove. This part adds another layer of flavour and it looks super cute, but it’s optional because biting into cloves can be a bit intense.
Prepare ham for the oven by placing onto a large, lined baking try, then smother it with about a third of the marinade. Add water to the bottom of the baking tray then loosely cover the whole ham with foil (lined with baking paper) and bake for 15 minutes. Remove from the oven and bush on more of the marinade. Cover and bake for another 15 minutes. Turn oven up to 200°C, then remove the cover from the ham and baste with marinade again, ready for the final bake. Cook for a further 15 minutes. Don’t worry if it caramelizes deeply and goes quite dark, that’s the sugar at work adding loads of flavour. Just watch that it doesn’t burn. Combine baking tray juices and any unused marinade together and set aside. Set ham aside also to rest.
Over a medium heat cook reserved marinade and pan juices in a pan on the stove top. Reduce by about a third to a half (depending on how thick it was to start with) until the sauce has thickened and set aside.
Over a medium heat in a fry pan, dry fry walnuts until they are toasty, remove from heat and sprinkle with Lee Kum Kee Pure Sesame Oil, toss gently and set aside.
Keep the oven hot at 200°C. In a large bowl, add cornstarch and garlic powder to sweet potato and coat each side, add 2 tbsp oil and 2 tbsp Lee Kum Kee Premium Soy Sauce, toss well, then bake in single layers on two lined baking trays for around 20 minutes, or until cooked and golden. Turn each piece at the halfway mark. In the last five minutes, toss in walnuts and thyme, then remove from the oven and serve with fresh thyme as garnish.
To serve ham, cut it into slices and serve on a platter with sauce and sweet potato fries.