In general the lower to the ground the vegetables are, the better chance of overwintering because the snow provides protection or the plants
are less exposed to cold winter winds.
I don't grow parsnips but have heard that they taste better after many frosts have made them sweeter. They take a long time to grow, at least 100 days to maturity. If you mulched them with leaves and protected them with a tarp or row cover you could harvest them all winter long so long as the ground isn’t frozen.
Spinach, kale, carrots are other choices.