Preheat the oven to Gas 4, 350°F, 180°C, 10 mins before baking potatoes.
Boil potatoes in skins for 20 mins.
Cool, then peel and slice thickly.
Place in small roasting pan.
Heat the sugar, 4 tbsp water and butter until well mixed.
Pour over potatoes and bake for 30 mins, basting frequently with syrup.