Many people cook the spuds on the day they plan to tuck into a roast dinner, or in December, a Christmas feast.

Spitting-hot oil and goose fat tend to be the ingredients that are relied upon the most to make the skins perfectly crispy, but one chef has claimed that it comes down to something else.

Kush Bhasin, now a chef at Sorted Food, has worked in numerous Michelin-starred kitchens including as a development chef to Raymond Blanc at Le Manoir aux Quat’Saisons.

With the countdown on to December 25, the cooking expert has revealed his foolproof method to ensure your roasties get the “perfect crunch with a fluffly middle”.

He claimed that preparations should start “up to five days ahead of the big meal”, which for most, is December 20.

The chef continued: “Boiling them the day before or up to five days before, means they completely dry out and will absorb the fat better.”

But first, Kush urged cooks to get their shopping list correct by sticking to Kind Edward potatoes rather than Maris Piper or similar.

He explained that they have the highest dry-,matter content and lowest sugar levels which helps in securing a “dry, crispy outside”.

Once they’ve been purchased (at least five days before you plan to eat them), the chef suggested that they should be cooked sharpish.

How to cook crunchy roast potatoes

Start by peeling the potatoes and halving each one rather than quartering, as Kush claimed that they’re better large.

Next, add them them to a pan of heavily salted, boiling water which according to the chef, “should be as salty as the sea”.

Reduce the heat to a tiny simmer and once the potatoes start to fall apart and “peel”, they are ready. This should take 20-30 minutes if done correctly.

Once they are cooked, drain the potatoes thoroughly then carefully transfer them on to a cooling rack so they can fully dry out on all sides. Kush suggested: “Refrigerating them overnight is a bonus.”

If they’re being served in a few days time, leave the boiled spuds in an airtight container in the fridge until the time comes to roast them.

On the day, pre-heat a roasting tin with goose fat in an oven set at 220C.

According to Kush, the fat needs to be as hot as the oven, take care when putting the roast potatoes in the tray by using tongs to move them one at a time.

Every single potato must sizzle as it hits the goose fat so it’s important to not stack them up and instead, keep to one flat layer.

Douse them in the goose fat so they are completely covered, then cook the spuds in the oven at 220C for 20 mins, then reduce the oven to 180C and cook them for a further 20 minutes. When you turn the oven down, rotate all the potatoes so they get an even colour.

The chef said: “When they are finished, they should be held together like glass and crack with a loud crunch when you take a bite, yet still have a deliciously moist centre. Potato perfection! “