These were a huge hit with both of my daughters, and went over very well with the playgroup mommies (they taste great with coffee!). I was hesitant to tell people what was in them, since once I said "parsnip", I got some funny looks. But the proof is in the pudding (or... muffin) on these, and they were fantastic.
I substituted a mix of whole wheat and all-purpose flours, as suggested in the notes, and I took the sugar down to 3/4 cup - and they were still quite sweet. But then, I was using canned pineapple, because... well, I had it on hand! So that may have helped sweeten them up even more.