“Grandmas are moms with lots of frosting” is a popular Mother’s Day saying that has been printed on many images. “Grandmas are moms with lots of frosting” was printed on the newsgroup alt.books.dean-koontz on November 12, 2001. Authorship of the saying is unknown.
 
 
Google Groups: alt.books.dean-koontz
ACK!
Staci
11/12/01
DAWN!!! That would be amazing!
—
  Staci
“Grandmas are moms with lots of frosting.”
     
18 October 2004, Daily Republican Register (Mt. Carmel, IL), “Grandmothers 10: by Jami Maday, pg. 1, col. 1:
An unknown author once quoted, “Grandmas are moms with lots of frosting.”
 
1 March 2005, Courier-News (Bridgewater, NJ), “Senior moment” by Roz Cohen, Senior Scoop sec., pg. 2, col. 3:
I just want this baby to know that “Grandmas are moms with lots of frosting.” (Unknown author)
 
Google Books
How Grand You Are
By Sarah Arak
Silverback Books Incorporated
2006  
Pg. 39:
GRANDMAS ARE MOMS WITH LOTS OF FROSTING! — Author Unknown
     
Google Groups: alt.penpals.forty-plus-yrs
Grandparents ...
Buff
2/14/06
(...)
Grandmas are mums with lots of frosting. ~Author Unknown
 
Google Books
It’s Fun to Be a Grandma
By Becky Freeman Johnson
Eugene, OR: Harvest House Publishers
2007
Pg. 99:
Grandmas are moms with lots of frosting.
AUTHOR UNKNOWN
 
Patch
Funny, Poignant Grandparenting Quotes
In honor of National Grandparents Day, Sept. 11, here is the Grandparents Day song and a variety of quotes about grandparents.
By Kimathi Lewis, Neighbor | Sep 7, 2011 5:49 am ET | Updated Sep 8, 2011 8:51 am ET
(...)
Unknown
“Grandmas are moms with lots of frosting.”
 
Latin Times 
15 Mother’s Day Quotes To Tell Grandma How Special She Is!
By Natalie Roterman | May 08 2016, 11:26AM EDT
(...)
“Grandmas are moms with lots of frosting.” – Author Unknown
     
Bustle
9 Quotes About Grandparents For National Grandparents Day 2016
By KATHRYN KATTALIA
Sept 11 2016
(...)
8. “Grandmas are moms with lots of frosting.” — Author Unknown
   
Elite Daily
29 Instagram Captions For National Grandparents Day That Are Super Sweet
BY TESSA HARVEY
SEPT 8 2017
(...)
2. “Grandmas are moms with lots of frosting.”—Unknown
   
Good Housekeeping
30 Grandma Quotes to Honor Your Nana on Mother’s Day (And Every Day)
Whether you’re writing it in a card or saying it over the phone, it will mean everything to her.
By Selena Barrientos
May 9, 2019
(...)
Unknown
Grandmas are moms with lots of frosting.
 
YourTango
15 Sweet Grandma Quotes To Share With Your Grandmother On Mother’s Day
Emily Francos
May 11, 2019
(...)
5. Grandma’s are sugary sweet.
“Grandmas are moms with lots of frosting.” —Unknown