My friend Gil Palley (who I don't see often enough) would always pitch the song in D major so that after the usual verses he could change into D minor and sing:
"I'm Jewish, I'm Jewish, I'm Jewish, I'm Jewish, I'm Jewish till I die. . ."
(the practice of taking a perfectly good song and switching from major to minor can be lots of fun for those of us with little taste. Gil and I also used to butcher "Oi, dem Golden Slippers" in much the same way)
Not that this helps with the origins of Methodist Pie; sorry Greg!