Parsnips convert their starches to sugars as they mature (which takes a loooong time) and sweeten further as the soil temperature drops. Parsnips in winter, along with pumpkin and potatoes, good oil and a little salt, all roasted until their edges are crispy and browned are a most satisfying and easy meal. Put a leg of lamb with them if you want, but there's so much flavour in the veg that you don't really need it. I wouldn't bother peeling them, just give a good scrub and take it away. We look forward to parsnip season every year.