Peel your potatoes, and cut into halves (or quarters depending on size). (Top Tip: Don't throw away your potato peelings, these make great crisps! Just sprinkle a little salt and pepper, any flavourings that take your fancy and pop them in the oven until golden and crispy.)
Place a large pan of water on the hob and bring to the boil. Once hot, add the potatoes and a generous pinch of salt.
Bring the pan back to the boil and cook the potatoes for 7 minutes.
Drain the potatoes really well, ensuring they are as dry as possible.
Return them to the empty pan and sprinkle over the flour. Place a lid on your pan, and using a tea towel or oven gloves, give the pan a really good shake, ensuring the potatoes get a bit bashed up and coated in the flour.
Once the potatoes have cooled, place your potatoes on a baking tray lined with greaseproof paper, making sure none of them are touching, and place in the freezer.
Once fully frozen tip the potatoes into a bag. Can be frozen up to 1 month in advance.
ON THE DAY
Heat your oven to 190C/fan 170C/gas 5.
Add your sunflower oil to a large, lipped baking tray and leave to heat up for 5 minutes in the oven.
Carefully remove the tray ensuring an even coating of oil on the bottom, then add your frozen potatoes.
Roast for 30 minutes then turn the heat up to 220C/fan 200C/gas 7 and roast for another 30 mins.
Turn the potatoes once and remove from the oven when crispy and gold. Sprinkle with salt to taste.