Start by peeling the potatoes with a sharp potato peeler. Cut each potato in half and then each half into 3-4 pieces.
Place the chopped potatoes in a large pot of cold, salted water. Set the pot over medium high heat and bring to a boil.
Cook until the potatoes are just tender then drain.
Allow the potatoes to steam dry in the colander for 10 minutes then shake to rough up the outside.
Preheat the oven to 220ºC/430ºF.
Heat a few tablespoons olive oil/fat in a large sheet pan, baking sheet or baking dish (I prefer using metal) for 10 minutes in the hot oven.
Carefully place potatoes into the hot oil then generously season with salt and sprinkle over a few teaspoons of vinegar.
Toss to coat, make sure they're in an single layer and then place in the oven and allow to bake for 30-40 minutes, turning half way through roasting, until the potatoes are golden brown and crisp.
Remove the potatoes from the oven, season to taste and serve immediately.