“Mmmmm…donuts.”…“Mmmm…chocolate.”, ect. Did the Simpsons invent this phrase or mearly make it popular?
What the heck kinda question is that???
Actually, I think that people did say this differently in the days before the Simpsons, people were a little more likely to say something like…
“mmm, MMM - MAStadon”
It’s pretty hard to communicate the stress pattern here, the first is said in a higher pitch than the second, and the second has slightly more emphasis. The word that follows (chocolate, beer, sacralicious) is streesed on the first syllable.
Homer’s way of saying it seems far more passive…my favorite:“Mmmmmmm…floor pie”
::applauds::
Your taste is impeccable.
My recollection is that in the baseball episode where Mr. Burns bought a team of ringers, this phrase was introduced.
Homer pinch-hit for Darryl Strawberry (you’ve done a fine job today, Darryl, but I’m going with percentages. You’re
a lefty, Simpson’s a righty), and, while he was being given a bunch of strategy talk by Mr. Burns, his mind wandered:
“I wish I was home right now eating a big bag of potato chips. Mmmmmmm…potato chips…” and, for the first time, Homer went into his catatonic thinking-about-something-he’d-like-to-eat trance.
AFAIK “The Simpsons” imbued the phrase “Mmmmmm…(food)” with the necessary ‘meaning-without-context’-ness that made
it something more than a literal phrase, and a cultural phenomenon.
In short, I think the answer to your question is ‘yes.’
It also has a tendency to pop into your head when something non-edible but with a foodlike name is mentioned…so I’m sitting in my Renaissance Drama class the other day, and I haven’t had lunch yet, and the professor is talking about Robert Greene’s play Friar Bacon and Friar Bungay…and I can hear Homer in my head, loud and clear: “Mmmmmmmm…Bacon…”
It was all I could do not to giggle. 
(BTW, my favorites are “sacralicious” and “incapacitating,” the latter referring to eggs with pepper spray.)
I feel I must point out that “Sacrelicious” is in reference to a waffle Bart stuck to the ceiling, which Homer thought was God.
Homer (to ceiling): Why do you mock me o Lord?!
Marge: That’s not God, that’s just a waffle Bart stuck to the ceiling. (Gets waffle down with broom; falls into Homers hands)
Homer (to waffle): I know I shouldn’t eat thee…(Bite) MMMmmm…Sacrelicious…
Yes, I am full of semi-useless Simpsons trivia.
**
IIRC, it’s “Ooooooo…floor pie.” This is one of the few items without the “Mmmm.” I have this wav on my computer and I’ve listened to it over and over.
Arrgg…missed the ‘latter’ there. Oh well. Now everyone knows what sacrelicious was in reference to.
Oh, and I think “Mmmm…” has just evolved into pop culture…not necessarily coming from the Simpsons, but just being made more popular.
“Mmmmm… Forbidden Donut…”
Yes, it was the Simpsons that popularized this.
best non-food use:
(Homer tilts chair back)
“…mmmmmmmmmmmm…slanty…”
How about good old Andy Griffith shilling Ritz(?) crackers on TV back in the 70’s?
“Mmmmm… good cracker.”
Second best: Homer eating the bride and groom from the top of the cake after Selma’s marriage to Troy McClure:
“Mmmmmmmm . . . point . . .”
It actually showed up in the first season, in “Krusty Gets Busted.” While in the Quik-E-Mart, Homer says, “Mmmm . . . chocolate.”
There’s a list of all Homer’s “mmmmmms” here.
mmmmmm…purple.
I think he only popularized it, just like people were probably doing stupid things and saying “Doh” long before Homer made it his catchphrase.
jharding, I’d forgotten about Andy Griffith’s pre-Homer use of the phrase. I’m surprised the Simpson’s writers haven’t used the good cracker line yet in tribute. Maybe in a Matlock reference.
Mmmm…Soylent Green
Mmmmmmmmmmm…Bop.
Had to take it there. 
I don’t know if this counts as tribute, but Milhouse’s father used to work at a cracker factory. In the episode where his Kirk and Luann divorce, the factory is shown. It’s motto is “The dryyyy cracker.”
Here’s an obscure Simpsons quote:
“Mmmmmm… steaky!”
It wasn’t said by Homer, though.
Steakie. The great taste of Worchestshire Sauce in a soft drink.
[while golfing]
Mr Burns: Use an open-faced club. A sand wedge.
Homer: Mmmmm…open faced club sandwedge. Glahglahglah (no one ever adds the drooling effect).
I always thought the forbidden donut was sacrilicious. It was frobidden because he sold his soul o the devil for it, thus he downed the last morsel and quipped “Mmmmm…forbidden donut…sacrilicous.” But I could be wrong.
Have we pretty much covered the General Question here?