Root Vegetable Gratin
Why This Recipe Works
Our root vegetable gratin pairs the earthy flavor of potatoes with thinly sliced sweet rutabaga and savory celery root. We allow these flavors to come to the fore by adding just a few aromatics: onion, garlic, thyme, and Dijon mustard. We add white wine to the gratin because the wine’s acidity strengthens the pectin in the potatoes so that they remain intact while the denser, less-starchy rutabaga and celery root cook through; the wine also brightens the flavor of the vegetables. To help the top layers of the gratin cook through at the same rate, we cover the dish for the first portion of the cooking time. A layer of Parmesan-enhanced panko bread crumbs added after the foil is removed toasts while the gratin finishes cooking, adding a crispy, golden crust that is nutty and cheesy in flavor.