Sliced fennel makes a great substitute for potatoes in this crumb-crusted gratin. This recipe first appeared in the magazine Edible Portland; the recipe's author, Diane Morgan, writes that she’s served the dish at Thanksgiving for 15 years.
I can't tell you how many times I've heard guests say, "Fennel? I've never tasted fennel. This is delicious." Whether sautéed, braised, or sliced raw for salads, fennel is always a surprise and a delight to serve. Sometimes labeled sweet anise, fennel has a texture similar to celery and a lovely, mild licorice flavor, which is a perfect foil for a rich meal. This gratin dish has been a part of my Thanksgiving buffet for at least 15 years—it's now a tradition for us, and my family would be disappointed to do without it.