“Whatever butters your biscuit”

“Whatever butters your biscuit(s)” means “whatever makes you happy” or “whatever’s your choice/desire” or “whatever’s your flavor” or “whatever turns you on” or “whatever floats your boat.” The silly saying is cited in print from at least 1996.
 
Similar food-related phrases include “Whatever melts your butter” (since 1975), “Whatever bakes your cake” (since 1997), “Whatever tickles your pickle” (since 1998) and “Whatever sprinkles your donut” (since 2012).
   
 
Urban Dictionary
whatever butters your biscuit
basically synonymous with most other phrases fitting the pattern of “whatever __ your __,” such as whatever floats your boat
can I substitute cheese grits for hash browns?
sure, whatever butters your biscuit. 
by cultureG33K Jul 10, 2007
   
Google Groups: rec.arts.tv.mst3k.misc
Newsgroups: rec.arts.tv.mst3k.misc
From: .(JavaScript must be enabled to view this email address) (Mr. Noah S. Singman)
Date: 1996/09/07
Subject: Re: WOTP: LA LA LA LA…
 
Hey, whatever butters your biscuit.
   
Google Groups: rec.arts.tv.mst3k.misc
Newsgroups: rec.arts.tv.mst3k.misc
From: Noah Singman

Date: 1997/08/20
Subject: Re: The Spirit of Newsgroups Past
 
Hey, whatever butters your biscuit
 
Google Groups: alt.shoe.lesbians.moderated 
Newsgroups: alt.shoe.lesbians.moderated
From: .(JavaScript must be enabled to view this email address) (swade)
Date: 1998/04/03
Subject: Re: Porn on the Cob (was Re: southern sayin’s)
 
whatever butters your biscuit
whatever paddles your canoe
whatever grinds your gears
whatever sizzles your bacon
   
Google Books
Longarm in Devils River
By Tabor Evans
New York, NY: Jove Books
2008
Pg. 21:
“Fine by me. Whatever butters your biscuits just suits me right down to the ground, mister.”