In classic pommes Anna, thinly sliced potatoes are layered in a pan with clarified butter, cooked until tender, then inverted to reveal the crisp, golden crust that formed on the bottom of the “cake.” Our version skips the clarified butter, layers parsnips in with the potatoes for earthy sweetness, and seasons it with thyme and rosemary. You will need a few specific kitchen items to prepare this recipe: a Y-style peeler for shaving the parsnips, a mandoline for slicing the potatoes, a 10-inch oven-safe nonstick skillet and an 8- or 9-inch round cake pan to compress the cake as it cooks. The potatoes can be peeled in advance and refrigerated in for a few hours, but don't slice them until ready to cook; the slices quickly discolor. Better yet, pommes Anna can be made ahead and reheated: Allow the unmolded potato cake to cool to room temperature, transfer to a large plate, cover with plastic wrap and refrigerate for up to two days. When you're ready to serve, cut the chilled cake into 8 wedges, place on a parchment-lined baking sheet and heat at 450°F for 10 to 15 minutes.