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A browned fennel potato gratin, garnished with rosemary in an oval casserole dish with handles and a glass of white wine on either side of the dish.
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5 / 4 votes

Fennel Potato Gratin

This fennel potato gratin, made with layers of thinly sliced fennel and potatoes, and a thick creamy white Cheddar sauce, is one of the most comforting side dishes we've ever experienced.
Prep Time45 minutes
Cook Time1 hour
Total Time1 hour 45 minutes
Course: Sides
Cuisine: American
Servings: 8 servings
Calories: 340

Ingredients

  • 3 tablespoons (1 1/2 oz) butter, plus more for the baking dish
  • 1 shallot, sliced
  • 1 garlic clove, minced
  • 2 tablespoons all-purpose flour
  • 1 1/4 cups half-and-half, plus more if needed
  • 1/2 block (10 oz) sharp white Cheddar cheese, shredded
  • 1/2 teaspoon salt
  • 1/4 teaspoon freshly ground black pepper
  • 1/8 teaspoon ground nutmeg
  • 2 pounds baking potatoes, such as russets (2 to 3 large), peeled and thinly sliced
  • 8 ounces fennel bulb (1 medium), thinly sliced and fronds reserved
  • Fresh rosemary leaves, to garnish
  • Chopped fennel fronds, to garnish (optional)
US - Metric

Instructions

  • Preheat the oven to 400°F (204°C) and adjust an oven rack to the middle position. Lightly butter a broiler-safe 2-quart (1.9-liter) baking dish.
  • In a heavy saucepan over medium heat, melt the butter. Add the shallot and cook, stirring occasionally, until tender, 2 to 3 minutes. Stir in the garlic and cook, stirring, for 1 minute more.
  • Sprinkle in the flour and cook, whisking constantly, for 1 minute. Gradually whisk in the half-and-half and cook, whisking constantly, until thickened and bubbly, 3 to 6 minutes.
  • Remove from the heat and whisk in the cheese until it melts and the sauce is smooth, 2 to 3 minutes. Stir in the salt, pepper, and nutmeg. If your sauce seems exceptionally thick, thin it with a little additional half-and-half.
  • Layer the potato and fennel slices alternately in the prepared baking dish. You should have 3 to 4 layers.
  • Spread the cheese sauce over the fennel and potatoes and cover the dish with aluminum foil.

    ☞ TESTER TIP: If your baking dish seems quite full, place the dish on a rimmed baking sheet lined with foil before baking in case the gratin bubbles over.

  • Bake until the potatoes are tender, 50 to 70 minutes.
  • Remove the gratin from the oven, adjust the oven rack to 5 inches (13 cm) from the heat, and set the oven to broil. Uncover the dish and broil until golden brown, 2 to 4 minutes.
  • Let the gratin rest for at least 10 minutes. Garnish with rosemary and, if desired, the snipped reserved fennel fronds.

Notes

  1. Make in advance--Assemble and bake the gratin up to 24 hours in advance. Let cool, cover with foil, and stash in the fridge. Reheat in a 350°F oven, covered, until heated through, then remove the foil and broil, as instructed in step 8.
  2. Use a mandoline--A mandoline will give you even thin slices of potato and fennel.
  3. Storage--Leftover gratin can be kept in a sealed container in the fridge for up to 4 days.

Nutrition

Serving: 1portion | Calories: 340kcal | Carbohydrates: 27g | Protein: 13g | Fat: 21g | Saturated Fat: 12g | Monounsaturated Fat: 5g | Trans Fat: 0.2g | Cholesterol: 60mg | Sodium: 422mg | Fiber: 3g | Sugar: 4g