Preheat oven to 125C/Gas 1/2.
1) Parboil potatoes for 4 minutes in a large pot over medium heat, or pierce with fork and microwave for 6 minutes. When ready, cut into 8 wedges each and sprinkle with vinegar.
2) In large skillet, heat the extra-virgin olive oil over medium-high heat, add the bacon and cook until crisp. Remove with a slotted spoon to drain on kitchen paper.
3) Toss potatoes in the bacon drippings and season with sugar, and salt and pepper. Scatter onto a baking tin and roast, in the preheated oven, until golden and crisp, about 20 minutes.
4) Transfer potatoes to a serving bowl and toss with the parsley and the reserved bacon.