A Popkin is All-World's name for a sandwich. It seems to be the most popular food in Roland's word. On Delta Flight 910, when Roland is offered a "sandwich" from Jane Dorning, it is through Eddie Dean's mind that he associates it with a popkin. In our-world, "popkins" can comprise of many things: meats, vegetables, sauces, etc. So it may be so in All-World as well.
A Popkin is All-World's name for a sandwich. It seems to be the most popular food in Roland's word. On Delta Flight 910, when Roland is offered a "sandwich" from Jane Dorning, it is through Eddie Dean's mind that he associates it with a popkin. In our-world, "popkins" can comprise of many things: meats, vegetables, sauces, etc. So it may be so in All-World as well.