Don't get all hung up on the parsley root, although if you can find it use it. Parsnips are an excellent substitute, but so are carrots of any color, turnips, rutabagas or celery root. Or use a variety. Ideally you will have skin-on thighs here, but this recipe works with skinless thighs, too. Obviously chicken thighs are a good sub if you don't have pheasant, and turkey -- wild or domesticated -- works, too, as would the thighs off a ruffed grouse. The one thing not to skimp on is the roasted garlic. Yes, you want two whole heads. Don't be scared: The flavor sweetens and mellows once the garlic has been roasted. If you don't know how to roast garlic, read this tutorial.
Serve this dish with a full-bodied white wine such as a Cotes du Rhone, Chardonnay, Viognier or an off-dry Riesling. For beer, go with a crisp lager or a pale ale. Once made this will keep in the fridge for a week.