📝 About This Recipe
This elegant gratin marries the earthy, nutty undertones of celeriac with the bright, honeyed sweetness of Braeburn apples. Bathed in a luxurious garlic-infused cream and topped with a crisp Gruyère and sourdough crust, it offers a sophisticated twist on the classic potato gratin. Perfect for a holiday centerpiece or a cozy Sunday roast, this dish celebrates the rustic beauty of cold-weather produce.
🥗 Ingredients
The Produce
- 2 pounds Celery Root (Celeriac) (peeled and sliced into 1/8-inch rounds)
- 2 large Braeburn or Honeycrisp Apples (cored and sliced into 1/8-inch rounds)
- 2 pieces Shallots (finely minced)
- 3 cloves Garlic (smashed and minced)
The Cream Sauce
- 1.5 cups Heavy Cream (full fat for best results)
- 1/2 cup Whole Milk
- 1 tablespoon Fresh Thyme (leaves stripped from stems)
- 1 teaspoon Fresh Sage (finely chiffonade)
- 1/4 teaspoon Nutmeg (freshly grated)
- 1.5 teaspoons Kosher Salt (or to taste)
- 1/2 teaspoon Black Pepper (freshly cracked)
- 2 tablespoons Unsalted Butter (for greasing the dish and sautéing)
The Topping
- 1.5 cups Gruyère Cheese (freshly grated)
- 1/2 cup Sourdough Breadcrumbs (coarsely ground)
- 1/4 cup Parmesan Cheese (finely grated)
👨🍳 Instructions
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1
Preheat your oven to 375°F (190°C). Generously grease a 9x13 inch ceramic baking dish with one tablespoon of butter.
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2
Prepare the celery root by cutting off the top and bottom, then using a sharp knife to slice away the rough outer skin until only the white flesh remains.
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3
Using a mandoline or a very sharp chef's knife, slice the celery root and the cored apples into uniform 1/8-inch thick rounds. Keep them separate for now.
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4
In a small skillet over medium heat, melt the remaining tablespoon of butter. Sauté the minced shallots and garlic for 3-4 minutes until translucent and fragrant, but not browned.
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5
In a medium saucepan, combine the heavy cream, milk, sautéed shallots/garlic mixture, fresh thyme, sage, nutmeg, salt, and pepper. Bring to a very gentle simmer over low heat, then remove from heat immediately.
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6
Begin layering the gratin by shingling the celery root and apple slices in the prepared dish. I recommend an alternating pattern: two slices of celery root for every one slice of apple to balance the sweetness.
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7
Once the dish is tightly packed with the produce, pour the warm cream mixture evenly over the top. Use a spatula to gently press down on the slices to ensure the cream penetrates the layers.
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8
Cover the baking dish tightly with aluminum foil. This allows the celery root to steam and soften before the cheese topping is added.
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9
Bake in the center of the oven for 40 minutes. The celery root should be fork-tender when tested through the foil.
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10
While the gratin bakes, toss the grated Gruyère, Parmesan, and sourdough breadcrumbs together in a small bowl.
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11
Remove the foil from the dish. Sprinkle the cheese and breadcrumb mixture evenly over the top of the gratin.
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12
Return the dish to the oven, uncovered, for another 20-25 minutes. Bake until the cream is bubbling and the top is a deep, golden brown.
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13
For an extra-crispy finish, you can broil the gratin for the final 1-2 minutes, watching closely to prevent burning.
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14
Remove from the oven and let the gratin rest for at least 10 minutes before serving. This crucial step allows the sauce to thicken and set.
💡 Chef's Tips
Use a mandoline for slicing to ensure uniform thickness; this ensures everything cooks at the same rate. Choose firm, tart apples like Braeburn, Pink Lady, or Granny Smith so they hold their shape during the long bake. Don't skip the resting period; the gratin will be watery if served immediately out of the oven. If the top browns too quickly before the celery root is soft, tent it loosely with foil for the remainder of the bake. To make it vegetarian-friendly, ensure your cheeses are made with vegetable rennet.
🍽️ Serving Suggestions
Serve alongside a herb-crusted roast pork loin or a succulent roasted chicken. Pair with a crisp, dry white wine like a Chenin Blanc or an Alsatian Riesling to cut through the richness. A side of simple dressed arugula with lemon vinaigrette provides a perfect peppery contrast. Excellent as a vegetarian main course served with a side of roasted Brussels sprouts and walnuts. For a holiday spread, garnish with a few fried sage leaves for a professional touch.