Place the potatoes in cold salted water, bring to the boil and simmer until just beginning to get tender.
Drain the potatoes and give them a really good shake to fluff up all the edges.
Place them on a cooling rack or leave them in the colander If you don't have one - to steam dry. You can freeze them at this point if you like.
Heat the oven to 220C (or as close to this as you can if you're cooking other things).
Heat a good couple of glugs of 50/50 vegetable oil and olive oil in a thin bottomed roasting tin until hot.
Tip in the potatoes, turn them over until coated.
Be very generous with the sea salt flakes.
Roast until crisp and golden, turning them over a couple of times in the pan and shaking them around in the hot oil.
