6-8 large floury potatoes (Coliban in particular or Sebago are great for roasting here in Oz), peeled + cut into halves + or quarters if the potatoes are very large.
A few sprigs fresh rosemary
Pre-heat oven to 200˚C/392 ˚F
Add 1/3 cup canola oil to a large baking tray, place in the pre-heated oven to heat the oil.
Half-fill a large pot with cold water, add a generous pinch of salt, add the potatoes and bring to the boil over high heat. Par boil until slightly softened, you want the potatoes to be just cooked through when tested with a knife, but not so much that they will be overly boiled and fall apart totally when drained.
Drain potatoes then return them to the pot, cover with the lid then give the pot a really good shake to roughen up the edges of the potatoes and encourage them to become really fluffy. If you like use a fork to fluff up the tops of the potatoes even further by scraping any lose potato on top into little mounds on top.
Using a pair of tongs carefully add the par-cooked potatoes into the hot oil and season tops with a sprinkling of sea salt. Scatter some rosemary leaves around the tray then roast potatoes for 1-1 1/4 hours or until they are super crunchy and crisp.