Julienne the carrots, parsnip and the broccoli. Slice the onion thin.
In a bowl whisk together the mayonnaise, sour cream, cider, vinegar, and chives.
Toss the julienned vegetables into the dressing and stir to combine. Add salt and pepper to taste.
Refrigerate until you are ready to serve. It is best to let the flavours meld for at least one hour, but overnight is best.