There's an ambiguity here between palindromic words and palindromic sentences (where punctuation and spacing are non-breaking):

"Go hang a salami, I'm a lasagna hog"

or

"A man, a plan, a canal, Panama"

though it seems that all of the answers (in the one tutorial and one round that I played) are single words, often slid in as character insertions. Just go light on the spacebar, apparently.