Where did peanut butter and jelly sandwiches originate?

Context: The first known reference for a peanut butter and jelly sandwich appeared in the Boston Cooking School Magazine in 1901; it called for "three very thin layers of bread and two of filling, one of peanut paste, whatever brand you prefer, and currant or crabapple jelly for the other", and called it as "so far as I know original".

Answer: In 1901, the Boston Cooking School Magazine published the first known reference for a peanut butter and jelly sandwich. This magazine article called for "three very thin layers of bread and two of filling, one of peanut paste, whatever brand you prefer, and currant or crabapple jelly for the other."