The perfect roast spud

People are generally complementary about my roast potatoes, although to me the quality varies a little from one dinner to the next. So what are the things that contribute to getting it right?

Well, as usual I start with Delia Smith's recipe (http://www.deliaonline.com/recipes/perfect-roast-potatoes.html) but I've modified it over the years.

Firstly, the variety is important. This varies from country to country so you can't go by her specification of Desiree potatoes. Records work well in Ireland. In Belgium I used Francelines. In Switzerland and France I look for a variety which is specified as being good for puree or boiled potatoes.

The potatoes should all be about the same size, which means that larger ones should be cut in half - or even in three. I

Then parboiling is essential. You can do potato wedges or cubed roast potatoes with garlic and rosemary without parboiling but the traditional roast spud needs to be parboiled. Having misread Delia's recipe the first time, instead of pouring boiling water over the potatoes and simmering them for 10 minutes, I put them in cold water, brought it to the boil and then simmered it for 10 minutes. That turned the potatoes to mush - not surprisingly, with hindsight (so I mashed them!). After that, I reduced the simmering time to 5 minutes and that generally works. So either bring to the boil from cold and simmer for 5, or add boiling water and simmer for 10. The idea is to soften the outside of the potato but not to cook it right through. Delia suggests testing the outside with a skewer, which is a good idea because otherwise the next step might not work as intended.

The next stage is to drain them, of course. The, holding the pan and lid tight, you give it a good shake - hard enough for the potatoes to bounce around. If you've done everything right this will roughen up the edges, making them floury, and result at the end in a crust that is crisp without being greasy.

What fat to use? Well, goose fat or duck fat are the best, while olive oil or sunflower oil are the healthiest. In general, you would use the fat from the roast meat - if you are serving them with roast meat. Whatever you do, it's essential that you get the fat sizzling hot by allowing it to melt in the oven before you add the potatoes. When you add them you make sure they get evenly coated with the fat before putting them into the oven.

Oven temperature for roast spuds, at about 220 degrees Celsius (200 for a fan oven, gas mark 7) is higher than that for roast meat. In practice, though, if you follow Delia's recipe to the letter you have to start the roasting before you take the meat out, even allowing for the fact that you need time for the meat to rest whereas the potatoes can't be done far ahead of time. Whenever I had a second oven I used that but if you don't have one you can still juggle. One trick is to use the oven grill combination with shorter cooking time. Ovens vary so I can't be more specific.

I disagree, though, that you don't need to turn them halfway through the roasting time. if you don't do that, you risk the side that is in contact with the tin getting leathery. I think you get a better overall finish if you turn them.

Finally, although they can't be done far ahead of time - and can't be taken out to "rest" the way the meat should - you do have wriggle-room to keep them warm for a short time if you're running late - by turning the oven right down.