Joanna's Cookbook: Perfect Potatoes

The best way to serve potatoes is simply to boil them and serve with butter and salt.
There is only one secret:
Old potatoes (peeled or in their jackets)are added to COLD salted water, brought to the boil and cooked until just tender.

New potatoes (lightly scrubbed) are plunged in HOT salted water and cooked until tender.