Try Fennel As An Ideal Substitute For Potatoes In Gratin

Crisp and mild, raw fennel is a delicious addition to salads and grazing boards. With a texture similar to celery and just a hint of mild licorice flavor, the raw vegetable is perfect for scooping up dips, and it adds a wonderful depth of flavor when simmered in vegetable soups. But one of the best and most surprising uses of fennel is to roast it au gratin in a creamy sauce. It's as easy as replacing potatoes in your favorite gratin recipe.

Most recipes use white potatoes for gratins, and when you think about it, the potatoes don't add much flavor — the creamy dairy sauce they're baked in is the real star of the show. Potatoes provide that satisfyingly starchy texture, but if you overbake a potato gratin, you'll wind up with a disappointing mash. Fennel keeps its texture much better and contributes a sophisticated flavor profile that makes the gratin a memorable side dish.

Fennel is in season during the cooler months, which is when it's at the height of flavor and texture, although you'll find it in most stores all year long. Look for firm white bulbs with no dark bruises or soft spots. The feathery fronds are edible and are great as a garnish or in salads. The stalks, however, are too fibrous to make good eating — save them for vegetable stock instead.

To substitute fennel in a gratin recipe, first prepare the bulb for baking. After cutting off the stalks, slice the bulb in half from top to bottom. Trim out the dense core, but leave enough for the layers of the bulb to hold together, then cut the fennel into slices about a half-inch thick. Layer raw slices into a buttered baking dish so they fit snugly. Simmer heavy cream with aromatics like shallot, garlic, and bay leaf, and then pour it over the waiting fennel. 

The gratin should bake until the fennel is tender when poked with a knife, about 30 minutes, depending on your oven and the depth of your dish. Top the finished dish with a generous pile of grated parmesan and broil it for a gooey, umami-packed finish, or sprinkle it with buttered breadcrumbs for crunch.