"A quesadilla is essentially a grilled cheese…

The Mexican “quesadilla” has been compared to the American “grilled cheese sandwich.” “In its simplest form, a quesadilla is a grilled cheese sandwich,” the Calgary (Alberta) Herald stated ion March 29, 1989. “The quesadilla, a Mexican version of a grilled cheese sandwich except that flour tortillas are used instead of bread, takes on new forms here” was published in the book Best Restaurants of San Francisco (1991). “A quesadilla is a grilled cheese sandwich made with tortillas” was printed in the book Nuevo Tex-Mex: Festive New Recipes from Just North of the Border (1998).

Reddit—grilledcheese held a poll on July 2, 2017—“Is a cheese quesadilla a grilled cheese?”

Wikipedia: Quesadilla
A Quesadilla (/ˌkeɪsəˈdiːjə/, Spanish: [kesaˈðiʝa]) is a tortilla, usually a flour tortilla but also sometimes made with a corn tortilla, which is filled with cheese and then grilled. Other items, such as a savoury mixture of spices or vegetables, are often added, then they are cooked on a griddle. A full quesadilla involves two tortillas filled with cheese and stacked on top of each other. Halves are a single tortilla filled with cheese and folded into a half-moon shape.

Wikipedia: Grilled cheese
A grilled cheese (or toasted sandwich) is a hot sandwich typically prepared by heating one or more slices of cheese between slices of bread, with a cooking fat such as butter, on a frying pan, griddle, or sandwich toaster, until the bread browns and the cheese melts. A grilled cheese may contain ingredients besides the bread and cheese, as long as the latter is the main focus.

29 March 1989, Calgary (Alberta) Herald, “Mexican snack offers nutrition” by Joanne Good, pg. C5:
In its simplest form, a quesadilla is a grilled cheese sandwich.

Add a few more ingredients and this Mexican snack becomes a complete meal that’s ready in minutes.

Quesadillas use tortillas instead of bread.

Google Books
Best Restaurants of San Francisco:
The San Francisco chronicle guide to fine dining
By Patricia Unterman
San Francisco, CA: Chronicle Books
1991
Pg. 226:
The quesadilla, a Mexican version of a grilled cheese sandwich except that flour tortillas are used instead of bread, takes on new forms here.

Google Books
Nuevo Tex-Mex:
Festive New Recipes from Just North of the Border
By David Garrido and Robb Walsh
San Francisco, CA: Chronicle Books
1998
Pg. ?:
A QUESADILLA IS A GRILLED CHEESE SANDWICH MADE WITH TORTILLAS.

Twitter
Kameron Hoffs‏
@IvoryTiger
Rhion’s home from school “Daddy, I had a grilled cheese sandwich, but instead of bread, it had a tortilla!” You mean a quesadilla? YES! 😊
4:32 PM - 27 Nov 2007

Twitter
🎃Chris MISKA-Tonick 🎃‏
@Chris_Tonick
Didn’t feel like cooking so I just made Quesadillas; & really, what is the quesadilla, if not the Mexican incarnation of a Grilled Cheese?
8:43 PM - 4 May 2009

Twitter
Keenan Jones‏
@KeenanAJones
A grilled cheese sandwich is like an American Quesadilla…
9:18 PM - 5 May 2009

Twitter
Shane Kearns‏
@grilledshane
Can a quesadilla be considered a grilled cheese? Thoughts?
9:09 PM - 26 May 2009

Google Books
The Tex-Mex Grill and Backyard Barbacoa Cookbook:
More Than 85 Sizzling Recipes
By Robb Walsh
New York, NY: Ten Speed Press
2010
Pg. ?:
A quesadilla is a grilled cheese sandwich made with tortillas.

Twitter
Yukon Cornelius‏
@willfersher
a quesadilla is just a mexicans version of a grilled cheese
2:03 PM - 17 Aug 2012

Reddit—Shower Thoughts
A cheese quesadilla is just a Mexican grilled cheese sandwich
submitted July 14, 2015 by crotchknees
COMMENTS
twoheartedgal
I work at a Latin restaurant and this is literally what I tell picky children that come in so they’ll still eat their food.

Reddit—grilledcheese
Could a quesadilla be considered a grilled cheese? (self.grilledcheese)
submitted May 14, 2017 by KittyKeesh
I mean, it’s grilled cheese between bread. No additives, so it’s not a melt. I argued this point for half an hour with a friend and now I’m asking you, dear subreddit

Reddit—grilledcheese
Is a grilled quesadilla a grilled cheese sandwich? (self.grilledcheese)
submitted June 22, 2017 by Daesthelos
context
If a grilled cheese sandwich consists of bread and cheese, and if a tortilla by definition is bread, then would not a ‘sandwich,’ consisting of cheese and two tortillas, which has been grilled, be a grilled cheese sandwich?
COMMENTS
Munchlax
It’s a Mexican grilled cheese.

Reddit—grilledcheese
Poll: Is a cheese quesadilla a grilled cheese? (self.grilledcheese)
submitted July 2, 2017 by xenonnsmb
Discuss. https://strawpoll.com/sdw2bg1

Reddit—grilledcheese
Is a quesadilla a grilled cheese? (self.grilledcheese)
submitted August 27, 2017 by americandream1159

Twitter
Alex Zumbuhl‏
@AlexZumbuhl
Have u ever noticed that a quesadilla is just a Mexican version of a grilled cheese
2:36 AM - 10 Sep 2017

Reddit—Shower Thoughts
A quesadilla is essentially a grilled cheese sandwich
submitted October 19, 2017 by oz____zo
COMMENTS
amateur_generalist
Most often with creamy jalapeño sauce 😊

“A quesadilla is essentially a grilled cheese sandwich”