Potatoes labelled simply “Whites”, I have always thought, are the poor relations of the maincrop world – the equivalent of robusta coffee, or the Aligoté grape. But the Whites on sale at my local greengrocer – White Bros, as it happens – are excellent. Roasted, they have a crunchy exterior and a creamy, earthily flavoured interior.
I have banged on about the best way to roast potatoes quite a few times. Essentially: I peel them, cut them up, put them in cold water with a little salt, bring them to the boil, and boil them for three to five minutes. I bash up the surfaces.
I do not think it essential to put them in hot oil or fat. (But of course if you have fat or dripping, you need to melt it.) I toss the potatoes in sunflower or olive oil, and roast them at gas mark 6/200C, turning them a few times, for about an hour.
The posts to which I've linked below may not be 100% consistent with what I've just written.
Heston's roast potatoes
Roast potatoes IV
Roast new potatoes