Par boil the potatoes in salted water until fork tender on the outside but still a little firm in the centre, drain off water and gently toss them in the pan a couple of times to just fluff up the edges a bit. Put in a large bowl and refrigerate. I usually do this the day before if cooking for a crowd as a time saver, but if making on the day leave in the fridge until completely cooled and they are holding together and firmer. Before cooking leave out to return to room temperature beforehand.

Preheat your oven to 200 (fan) or gas mark 7. Pour enough vegetable oil to just cover the entire base of the roasting tray by around 3-4 mm. Place in the oven and heat until the oil is really hot. This will take around 10 mins.

Take the potatoes and place them carefully into the hot oil as it'll sizzle and spit. Sprinkle over the garlic powder, dried rosemary (if using it), and turmeric then season really well with sea salt and white pepper. Using tongs gently turn the potatoes in the hot oil to coat all over.

Return to the oven and roast for around 45 mins. Take them out and add the sprigs of rosemary and turn them over in the oil. Drain off 90% of the oil carefully give the potatoes a shake, and using the back of a spoon slightly squish the larger ones down a bit, then return them to the oven. Turn the temperature down to 180 (fan). Roast for a further 15-20 mins until really crispy and golden. Serve up and enjoy! :)