Here are the lyrics from the John McCutcheon Website, http://www.folkmusic.com/lyrics/cut-cake. McCutcheon has this song on his Howjadoo, Live at Wolf Trap, and Water From Another Time albums. I think he sings it at every concert he does.

CUT THE CAKE
(words & music by Tina Liza Jones)

We're gonna let 2nd grade out early today
Which made little Mikey kinda blue
He just turned 7 years old that day
And he thought he'd get a party at school
He walked back home and he's taken off his guard
There's chairs and tables all over the yard
And his friends jumped up and they hollered real hard,
"Happy Birthday to You!"

CHORUS:

It makes me think of the good old days
Happy birthday to you
You sure grew out of your baby ways
Happy birthday to you
(7th 23rd, 92nd) birthday we wish you many more
Health and wealth and friends by the score
Cut the cake and let's eat some more
Happy birthday to you

Now Mike's 22 and he's working for his Pop
And his head's full of business thru and thru
He was planning out a whole new system at the shop
And he forgot he had a birthday due
He drove back home and he's taken off his guard
There's chairs and tables all over the yard
And his friends jumped up and they hollered real hard,
"Happy Birthday to You!"

CHORUS

Now it's old man Michael in a rocking chair
Admiring the view
He's still got all his teeth and he's still got all his hair
And today he's 92
He turns in his seat and he's taken off his guard
There's chairs and tables all over the yard
And his friends jumped up and they hollered real hard,
"Happy Birthday to You!"

CHORUS

McCutcheon recording from Howjadoo: https://www.youtube.com/watch?v=Ks412SLFsV8