I steam them for just 10 minutes, then put them in the bottom pan of the steamer(emptied of water) add veg oil, put the lid on and shake vigourously - they should now have a fluffed up oiled outer, into a roasting pan into the oven and cook for 35-45 minutes until perfect.
the type of potato used makes a big difference, maris pipers are good using this method- or king Edwards.
Grendel