“How do you fix a broken pizza?”/“Tomato paste.”

A popular pizza joke is:
 
“How do you fix a broken pizza?”
“Use tomato paste!”

 
The joke has been cited in print since at least 1993.
 
 
Google Books
Silly School Jokes
By Gary Perkins and Dan Nevins
Mahwah, NJ: Watermill Press
1993  
Pg. 18:
How did the cafeteria cook glue the broken pizza back together?
With tomato paste.
 
17 October 1996, Lawrence (KS) Journal-World, “Ammunition for a boring day? Fresh supply of bad jokes” (Newsday), pg. 1D, col. 2:
How do you fix a broken pizza?
With tomato paste.—Angelo DeMeo
 
11 May 1997, Cedar Rapids (IA) Gazette, Yak’s Corner, comics section:
HOW DO YOU FIX A BROKEN PIZZA?
Use tomato paste!
 
Google Groups: alt.med.cfs
HUM: Kids Are Punny
Steven Du Pre
3/9/98
(...)
*How do you fix a broken pizza?
With tomato paste.
   
Twitter
Hourly Facts
‏@factstorm
How do you fix a broken pizza? Use tom…-  How do you fix a broken pizza? Use tomato paste. http://bit.ly/43yNpZ
11:36 AM - 17 Jul 2009
 
Twitter
Monicals_Pizza
‏@Monicals_Pizza
#TellAnOldJokeDay How do you fix a broken pizza? Tomato Paste #monicals
1:05 PM - 24 Jul 2014