A “quesadilla” isn’t a “case of dillas,” but there are jokes.
   
“Wasn’t Homer the guy that turned down the offer of a quesadilla. As I recall he said ‘better make it one dee-a, I don’t think I could eat a whole case’” was posted on the newsgroup alt.fan.british-accent/ on August 16, 1999. “I’d get the quesadillas, but I don’t think I could eat a whole case” was posted on the newsgroup alt.religion.kibology on March 31, 2004.
 
This was posted on Reddit—Dadjokes on July 23, 2013:
     
Whenever I order quesadillas…
Me: “I’ll have the quesadillas please.”
Dad: “A whole case of dillas?! How about you just have one dilla then see how you feel.”
 
Other quesadilla jokes include “I love Mexican food them chicken case of ideas be so good fr,” “Quesadiarrhea” (quesadilla + diarrhea; “case of diarrhea”) and “Why did Sherlock Holmes visit a Mexican restaurant?”/“Because he was looking for a good case idea.”
   
   
Wikipedia: Quesadilla
A quesadilla (/ˌkeɪsəˈdiːjə/; Spanish: [kesaˈðiʝa]) is a Mexican dish and type of taco, consisting of a tortilla that is filled primarily with cheese, and sometimes meats, spices, and other fillings, and then cooked on a griddle. Traditionally, a corn tortilla is used, but it can also be made with a flour tortilla, particularly in northern Mexico and the United States.
       
Google Groups: alt.fan.british-accent/
I’m Back!
Michael Spooner
Aug 16, 1999, 3:00:00 AM
(...)
Wasn’t Homer the guy that turned down the offer of a quesadilla.
 
As I recall he said “better make it one dee-a, I don’t think I could eat a whole case”.
     
Google Groups: alt.religion.kibology
Short, Shameful Confession
Tim Serpas
Mar 31, 2004, 11:06:28 AM
(...)
“I’d get the quesadillas, but I don’t think I could eat a whole case.”
   
Twitter
🅱🅸🅶 🅳🅰🅳🅳🆈 🅷🅰🅼🅼🅴🆁
@Bigdaddyhammer
Eating a quesadilla… Not sure if I can eat the whole case, though…
5:15 PM · Aug 9, 2009·Twitter Web Client
   
Twitter
its duhnelle not danyel
@duhnelle
My Grandma (to her husband):“Do you want a quesadilla?” Shannon: “maybe just a six pack, not a whole case”
6:06 PM · Feb 26, 2011·erased734497
   
Twitter
The Iron Greek
@thegoatwhocried
Asked my uncle to buy me a quesadilla.  His response?  “What’s a dilla, and why do you need a whole case of them?”
12:14 AM · Mar 26, 2012·Twitter for Android
   
Twitter
prison mike
@MikeHornick
I don’t even know what dilla is, so why would I want a whole case of it? #CaseODilla #Quesadilla
11:18 AM · Jul 26, 2012·Twitter for Android
   
Twitter
Local Bar Critic
@samuel_cpfresh
- I’m getting a quesadilla
- dude, you are getting a whole case of dilla?
1:20 AM · Jan 26, 2013·Twitter for iPhone
 
Reddit—Dadjokes
Posted by u/XanTheMan16 July 23, 2013
Whenever I order quesadillas…
Me: “I’ll have the quesadillas please.”
Dad: “A whole case of dillas?! How about you just have one dilla then see how you feel.”
     
Reddit—Dadjokes
Posted by u/Silent_Shadow_117 October 26, 2013
Friend’s dad just dad-joked me.
I was riding home with a friend and his dad when we passed by a Mexican restaurant. As we pass it, I mention that I really like their quesodillas, and then he chimes in with “Oh, I could never eat a whole case, I could only eat an each-o-dilla.”
 
Reddit—Dadjokes
Posted by u/FX114 February 28, 2014
“I’m going to have a quesadilla.”
“Really, a whole case of them?”
     
Twitter
Quesadillas Daily
@ilovedillas
“@allisonhaenny: you want a quesadilla ??? maybe start out with ONE dilla before you get a whole case of them!” Mo Dillas Mo problems
12:43 PM · Jan 20, 2015·Twitter for iPhone
 
Google Books
Dad Jokes:
The Punniest Joke Book Ever
By Editors of Portable Press
New York, NY: Simon & Schuster
2017
Pg. ?:
Kid: I want a quesadilla.
Dad: Wow, a whole case? Why don’t you start with one and go from there?
     
Twitter
Katie Cox WRTV
@KatieJoCox
Dad: “Whatcha having for dinner?”
Me: “Probably just a quesadilla and some chips.”
Dad: “A whole case? Beer isn’t… http://fb.me/5LAGNExBo
8:28 PM · Aug 30, 2017·Facebook
   
Twitter
Sabrianna Brianna
@digital_file
WAITRESS: Would you like to try a quesadilla?
ME: I can barely eat one dilla, let alone a whole case.
5:09 AM · Nov 6, 2017·TweetDeck
 
Reddit—Dadjokes
Posted by u/HanShotFirst17 April 6, 2018
Honey, I’m bringing you a quesadilla…
No need to Helen, I don’t need a whole case of them. One dilla is plenty.
   
Twitter
Russel Craig
@rgc226
@budweiserusa Server at restaurant: Would you like to start with a Quesadilla?  Dad: Do you have a 6 pack of Dilla? I don’t think I need a whole Case….
#KingOfDadJokes #BudweiserSweepstakes
1:04 PM · Jun 20, 2020·Twitter for iPhone
 
Reddit—Dadjokes
Posted by u/SafetyDanceInMyPants March 5, 2021
My wife offered to make me a quesadilla for dinner
I told her no. Whatever dilla is, I don’t think I could eat a whole case.