I wasn't joking - I can't remember who told me, but I doubt if it's true, or someone else on one of the threads about the meaning of the word would have come up with it.
The idea of calling a type of tune after something you could eat didn't strike me as at all unlikely - there's lots of tunes around with names like "Mistress Norton's Puffe". And of course in concerts of classical music you get "lollypops", short bits of enjoyable music to balance out the stuff that probably gets discussed at interminable length on some notional "Classical Mudcat Cafe", under the generic thread title "What is music?" and "Is this music?"
Moreover the very title Mudcat Cafe suggests the same kind of thinking.
Anyway, this is from a book of traditional Irish recipes by John Murphy. He calls it "flummery" - but it sounds a lot like what I was told was "Planxty".
Ingredients - oatmeal and water
Place the oatmeal in a broad deep pan, cover with water, stir, then let it stand for 12 hours. Pour off the liquid. Cover generously with fresh water, let it stand for another 12 hours, and so on for 12 more.
Pour off the water, strain the oatmeal through a course sieve and pour into a saucepan stirring continuously untiliot boils and thickens. Pour into dishes.
When cold, turn out onto plates, and serve with either wine & sugar, beer & sugar or mil. Cider and sugar is particularly recommended.