How to make the perfect roast potatoes

They’re a staple of our weekend roast - but what’s the secret to cooking the perfect roast potato?

Students from the Edge Hotel School think they’ve found the answer by calculating the exact mathematical measurements needed to get the crispiest, fluffiest roastie beating renowned chef Heston Blumenthal’s method in a recent taste test.

However, medical doctor turned food scientist Dr Stuart Farrimond believes it’s not all about size and you can still achieve a perfect potato by following the science behind the spud. We put them head to head in our very own taste test.

Serves: 4 - 6


1kg maris piper potatoes2tbsp olive oilTwo sprigs rosemarySalt and pepper to taste


  • Pre-heat the oven to 200C (400F)

  • Cut 1kg of potatoes

  • Drizzle with 2 tbsp olive oil (not extra virgin)

  • Season with salt and freshly ground black pepper

  • Toss the potatoes to coat

  • Get a shallow dark roasting tin (must be metal and dark to absorb more heat)

  • Arrange in a single layer, avoiding overcrowding to help steam escape evenly during the later stages of cooking

  • Sprinkle with 2 sprigs of fresh chopped rosemary

  • Cover the roasting tin tightly with a piece of aluminium foil or lid to seal in moisture

  • Place in the pre-heated oven.

  • Cook covered for 10-15 minutes so they cook first gently in their own steam to activate firming enzymes. Then remove the foil and return to the oven.

  • Roast for a further 35-40 minutes, or until the potatoes have browned around the edges.

  • Remove from the oven and serve warm