That is, it doesn't exist yet. No parsnip poetry has been gathered, nor has any been written to fill your life with parsnip-adoring writing.
Okay, so I prevaricated just a bit. A tiny inane limerick was found, the start, one hopes, of a lovely lyrical expression of parsnip adoration. We hope, we hope. Yes, soon we hope to see sonnets, to see odes and haiku and all sorts of lovely verse appreciating the marvelous, ever-amazing parsnip. Real soon. Real, real soon.
Um, yeah. So, here it goes...
There once was a parsnip named Millie
Who desired to taste quite vanill-y
But try as she might
She ne'er got it right
Tasted good, but dear Millie was silly.