Roasted Potato & Fennel Casserole

Featured in our Holiday 2025 Food + Entertaining article, The Simple Joys of the Season, this delicious roasted potato and fennel casserole is loaded with flavor and makes for the perfect side dish for any dinner.

Roasted Potato & Fennel Casserole
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Roasted Potato & Fennel Casserole

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Course: Sides
Servings

10

servings

Ingredients

  • 2–3 large potatoes, peeled and thinly sliced (about ⅛-inch thick)

  • 1–2 large fennel bulbs, trimmed and thinly sliced, fronds reserved for garnish

  • 1 large onion, chopped or sliced

  • 2-3 cloves garlic, minced

  • 1–2 tablespoons olive oil

  • 1 tablespoon butter

  • ½ cup chicken stock

  • ½ to 1 cup heavy cream (or half-and-half)

  • 1–2 cups shredded Gruyère or Parmesan cheese, divided (optional, for a richer gratin)

  • Salt and freshly ground black pepper, to taste

  • Fresh thyme leaves (optional)

  • 1 tablespoon flour (optional, for thickening the sauce)

Directions

  • Preheat your oven to 350 degrees and grease a large baking dish. Peel and thinly slice the potatoes and place them in a bowl of cool water to prevent browning while you prepare the other ingredients. Drain and let air dry before use.
  • In a large skillet, heat the olive oil and butter over medium heat. Add the sliced fennel and onion, and sauté until softened and slightly golden, about 10–15 minutes. Add the minced garlic and cook for another minute until fragrant. If using, whisk in the flour to coat the vegetables.
  • Gradually whisk in the chicken stock and heavy cream. Bring the mixture to a simmer, stirring continuously, until it begins to thicken slightly. If using cheese, stir in most of it (reserve some for the topping) and season with salt and pepper.
  • Arrange half of the potato slices in the bottom of the prepared baking dish. Top with half of the sautéed fennel and onion mixture. Pour half of the cream mixture over the first layer. Sprinkle with some of the reserved cheese and fresh thyme, if using. Repeat the layers with the remaining potatoes, fennel, and cream mixture.
  • Sprinkle the remaining cheese on top.
  • Cover the dish with aluminum foil and bake for 30–45 minutes.
  • Uncover and bake for another 30–45 minutes, or until the potatoes are fork-tender and the top is golden brown and bubbly.
  • Let the casserole cool for about 10 minutes before serving. Garnish with the reserved fennel fronds.

Notes