In 1939, President Franklin Delano Roosevelt and First Lady Eleanor Roosevelt prepared to receive a diplomatic visit from King George VI and Queen Elizabeth of Great Britain. Every detail of their visit had to be planned meticulously. Only the finest accommodations, food, and entertainment would be appropriate for the royal couple.

But on the second night of the King’s visit, Eleanor Roosevelt decided to break with protocol. She invited the King and Queen to come to the Roosevelt’s private cabin for an informal evening of real American entertainment. The royal couple accepted her invitation. At the cabin, they held a picnic with ham, turkey, baked beans, and strawberries. One item on the menu really puzzled the King. He had never seen anything like it. Mrs. Roosevelt explained that it was…