1) Preheat oven to 250C/Gas 9.
2) Parboil potatoes for 4 minutes in a large pot over medium heat, or pierce with fork and microwave for 6 minutes.
3) When ready, cut into 8 wedges each and sprinkle with vinegar.
4) In large frying pan, heat the extra-virgin olive oil over medium-high heat, add the bacon and cook until crisp. Remove with a slotted spoon to paper towels and reserve.
5) Toss potatoes in the bacon drippings and season with sugar, salt and pepper. Scatter onto a baking tin and roast, in the preheated oven, until golden and crisp, about 20 minutes.
6) Transfer potatoes to a serving bowl and toss with the parsley and the reserved bacon.