I have just discovered Jamie Oliver's roast potatoes and I am going to cook them like this on Christmas Day:
Par-boil the potatoes first and this gives them a "scrappy" surface.
Place in a baking dish and sprinkle Olive Oil and any herbs you may have e.g. rosemary.
Cook in a hot oven to what you would do ordinary roast potatoes.
Take them out of the oven and squash every one of the potatoes with a masher to flatten them out and this gives them more of a crunchy surface.
Turn them over once and when cooked place on an ordinary oven proof plate and keep warm in the oven.
I found this recipe amazing and I have been cooking for 50 years.