Ina Garten Root Vegetable Gratin

Ina Garten root vegetable gratin is a creamy, golden side dish with sweet potatoes, celery root and Gruyère that comes together in 2 hours 15 minutes. It's an easy make ahead side dish for Thanksgiving, Christmas or a cozy Sunday dinner, and it's great for feeding a hungry crowd.

Slice every vegetable a consistent 1/4 inch thick, because uneven pieces cook at different speeds in the cream. Skip that and you get a gratin with crunchy potatoes next to mushy sweet potatoes.

Ina Garten spent years making sweet potato gratins that never held together, since sweet potatoes have so little starch and just ended up floating in cream. Her fix was to mix them with celery root for sweetness and Yukon Gold potatoes for starch, so the gratin finally binds.

Source: Cooking for Jeffrey (2016)

Ina Garten Root Vegetable Gratin

0.0 from 0 votes

Course: Side DishCuisine: AmericanDifficulty: Easy

Servings

8

servings

Prep time

30

minutes

Cooking time

1

hour 

40

minutes

Calories

520

kcal

Layers of tender sweet potato, celery root and Yukon Gold sit in a Gruyère cream under a crisp bread crumb crust. A long, slow bake in a 350°F oven turns it bubbly and deeply golden on top.

Ingredients

• Good olive oil
  

• 1 1/2 cups sliced yellow onion (1 large)
  

• 2 cups (1/4-inch-sliced) fennel, top and core removed
  

• 1 tablespoon minced garlic (3 cloves)
  

• 1 pound sweet potatoes, peeled and sliced 1/4 inch thick
  

• 1 pound celery root, peeled and sliced 1/4 inch thick
  

• 1 pound Yukon Gold potatoes, peeled and sliced 1/4 inch thick
  

• 2 1/2 cups heavy cream
  

• 1/2 cup chicken stock, preferably homemade
  

• 2 cups grated Gruyère cheese (6 ounces with rind)
  

• 2 teaspoons minced fresh thyme leaves
  

• Kosher salt and freshly ground black pepper
  

• 2 1/2 cups coarse fresh bread crumbs, crusts removed
  

Directions

• Prep the baking dish: Preheat the oven to 350°F. Butter a 13 x 10 x 2 1/2-inch oval baking dish and set it aside.
• Cook the aromatics: Heat 2 tablespoons olive oil in a 12-inch sauté pan over medium heat, then add 1 1/2 cups sliced yellow onion and 2 cups sliced fennel. Cook for 10 minutes, tossing now and then, until lightly browned and tender, then stir in 1 tablespoon minced garlic for 1 minute.
• Mix the gratin: In a large bowl, combine the onion mixture, 1 pound sliced sweet potatoes, 1 pound sliced celery root and 1 pound sliced Yukon Gold potatoes. Then stir in 2 1/2 cups heavy cream, 1/2 cup chicken stock, 2 cups grated Gruyère, 2 teaspoons thyme, 1 tablespoon salt and 1 1/2 teaspoons pepper.
• Fill the dish: Pour the mixture into the prepared dish. Press it down lightly so the vegetables lie flat all the way to the edge.
• Add the topping: Toss 2 1/2 cups coarse fresh bread crumbs with 2 tablespoons olive oil. Spread them evenly over the top so the crust browns in one even layer.
• Bake the gratin: Bake uncovered for 1 1/2 hours. It's done when a small knife slides easily through the vegetables and the top is browned and bubbly.
• Rest and serve: Let the gratin set for 15 minutes before serving. Then scoop it out hot, since the cream thickens as it cools.

Tools for this recipe

• Benriner Japanese mandoline, Pyrex 9x13 glass baking dish, Victorinox Fibrox 8-inch chef's knife, Diamond Crystal kosher salt, 3 lb. As an Amazon Associate I earn from qualifying purchases.

FAQs

Can I make this gratin ahead of time?

Yes, and it's one of the best things about this dish. Assemble it, cover it and refrigerate for up to 24 hours, then bake it just before serving.

Do I need a mandoline to slice the vegetables?

A mandoline makes quick work of the potatoes and gives you even 1/4-inch slices. A sharp knife also works, and it's what Ina uses for the celery root, which is awkward on a mandoline.

What can I use instead of celery root?

Celery root brings sweetness and a nutty, earthy flavor, so a good swap is more Yukon Gold potatoes or parsnips. Keep the same 1 pound and slice it the same thickness so it cooks at the same pace.

Can I swap the Gruyère for another cheese?

Any good melting cheese with some nutty flavor will work, such as Fontina or white cheddar. Gruyère is the best fit because it melts smoothly and stands up to the sweet potatoes.

Why does my gratin come out watery?

The most common cause is cutting the vegetables too thin or too uneven, so they break down and release liquid. Slice them 1/4 inch thick and let the gratin rest for 15 minutes after baking so the cream can set.