I have always sung it:
"Pat-a-cake, pat-a-cake, baker's man
Bake me a cake as fast as you can.
Roll it, and pat it, and mark it with a B,
And put it in the oven for baby and me!"
But my in-laws sing it:
"Pat-a-cake, Pat-a-cake, baker's man
Roll 'em up, roll 'em up
Throw it in the pan!"
How do you "pat-a-cake"?