Step 1

Preheat the oven to 200 °C.

Step 2

Fill a large roasting tray with at least 1/2cm of the sunflower oil then add the rosemary and place in the oven to pre-heat.

Step 3

Peel the potatoes and slice into chunks no larger than 5cm/2 inches. Bring a large pot of water to the boil and season with the fine sea salt.

Step 4

Add the potatoes to the pot and cover with a lid. From the second the water begins bubbling again, cook the potatoes for exactly 8 minutes. Drain the potatoes and leave to steam in the colander for 3 minutes.

Step 5

Transfer the potatoes back to the pot and cover with the lid. Vigorously shake the pot up and down 4-5 times to break up the outside of the potatoes.

Step 6

Remove the baking tray from the oven and carefully transfer the potatoes to the hot oil (they should sizzle as they hit the oil). Use a spatula to gently flip each potato in the oil so that all sides are coated in a thin layer of oil.

Step 7

Place in the oven for 40 minutes, carefully flipping all the potatoes over at the half-way point.

Step 8

After 40 minutes check your potatoes, they should be lightly browned but still pale and undercooked in places. Remove the tray from the oven and drain off all the oil. Remove the rosemary then sprinkle the potatoes with the flaky sea salt. Return the potatoes to the oven for a further 10-15 minutes until they are crisp and golden brown. Serve the potatoes hot and fresh from the oven.