Is there anybody who doesn’t like mashed potatoes? For many Americans they are the one indispensable dish to serve on holidays, like, say Thanksgiving, even though at the first Thanksgiving there were no mashed potatoes. In fact, there were no potatoes at all. Though a New World crop, the potato would have to travel first to Europe, thanks to the Spanish conquistadors, and then return to these shores before it could become a staple crop in this country, aided by the experiments of one of America