Turn on your oven to 200C, add a couple glugs of olive oil into a baking dish and place in the oven to heat up
Place a large pot with water on a boil and add 3 large pinches of salt
Meanwhile peel the potatoes and slice in half at an angle
Once the water is boiling, add the potatoes along with 3 springs of fresh rosemary and boil for 10-12 minutes or until your knife can slide through them but with a little resistance
Drain the potatoes, removing just the rosemary stems (keep as many of the leaves as possible as they stick into the potatoes when cooking) and place the potatoes back into the pot you boiled them in, place the lid on and give them a couple firm shakes. This helps to break them up and to get nice and crunchy
Remove the baking dish from the oven, place the potatoes inside (you should hear them sizzling from the hot oil/dish).
Drizzle over a good few glugs of olive oil across the potatoes making sure each is covered evenly, along with a good few pinches of salt and pepper and place in the oven for 30 minutes
Remove from the oven, turn the potatoes so they cook evenly and place back in the oven for 25 minutes
Remove from the oven once again, add 4 or 5 springs of fresh rosemary and place back in the oven again for a further 5-10 minutes or until your desired consistency
If you are tight for time on Christmas Day or your oven just isn’t big enough to cook everything, then simply prepare these the day before and store in a large container with a lid and leave on your worktop overnight. Simply place them back in the oven for 15-20 minutes before serving to warm up! Ovens can differ quite a lot from each other, always keep and eye on them if your oven runs very hot as the time maybe faster for you!