“What’s Santa’s favorite sandwich?”/“Peanut butter and jolly.”

A Christmas riddle is:
 
Q: What’s Santa’s favorite sandwich?
A: Peanut butter and jolly.
 
The “jelly”/“jolly” pun was printed in many newspapers in December 1988.
 
       
3 December 1988, Noblesville (IN) Daily Ledger, “A Little Bit of Humor,” pg. 10, col. 4:
Frank: What is Santa Claus’ favorite food?
Fred: Peanut butter and jolly.
 
Google Books
Riddlemania
By Lori Miller Fox
New York,  NY: Sterling Publishing Company, Inc.
1991  
Pg. 25:
What’s Santa’s favorite sandwich?
Peanut butter and jolly.
   
Google Books
Kids’ Funniest Jokes
Edited by Sheila Anne Barry
New York,  NY: Sterling Publishing Company, Inc.
1993
Pg. 69:
What is Santa’s favorite snack?
Peanut butter and jolly.
NATALIE CHARETTE, 7
 
Twitter
Santa Claus‏
@Santa_Claus_
#SantaClaus My favorite Joke..  Q- What is the elves favorite kind of sandwich?  A- Peanut Butter and Jolly….. Ho Ho Ho
4:02 PM - 1 Aug 2008
   
Twitter
Santa Claus‏
@SantaClaus25
Replying to @vmunderground
@vseanclark Here is the latest favorite Joke up here. What is Santa’s favorite type of sandwitch? Why its peanut butter and JOLLY   Ho Ho Ho
9:56 PM - 13 Oct 2008
   
Google Books’
Laugh-Out-Loud Christmas Jokes for Kids
By Rob Elliott
New York, NY: HarperCollins
2016
Pg. ?:
Q: What is Santa’s favorite kind of sandwich?
A: Peanut butter and jolly.
 
Twitter
Medium Cindy Shelton‏
@MediumCindy
What’s #Santa’s favorite sandwich?
Peanut butter and jolly! #italktothedead #mediumcindyshelton #psychic #abundaceismine #Christmas
1:25 AM - 17 Dec 2017