Cooking, Baking & Cocktail Shaking

Potato Leek Gratin

If you’re looking for a comforting spring side dish, this Potato Leek Gratin is a delicious addition to any meal.

Potato Leek Gratin: This creamy spring side dish is loaded with cheese and topped with a toasted walnut crumble.

Yay, spring! We’re finally getting glimpses of warmer weather and shades of vibrant green buds are beginning to burst from the trees. Daffodils are beginning to showcase their vibrant lemon-yellow flowers and a handful of trees are in full bloom, flaunting an array of colorful buds. I secretly favor the cherry blossoms.

Potato Leek Gratin: This creamy spring side dish is loaded with cheese and topped with a toasted walnut crumble.

This Potato Leek Gratin was the result of a leftover leek in the veggie drawer. In most cases, the most delicious recipes are always unplanned and haphazard. Thankfully I’ve grown accustomed to writing down every single recipe. I learned that trait the hard after attempting to re-create several recipes from memory only to have said recipes turn out nothing like the original.

Live and learn, right? Except sometimes you have to live a few times before you pick up on the learning part.

Potato Leek Gratin: This creamy spring side dish is loaded with cheese and topped with a toasted walnut crumble.

Potatoes have been my go-to side dish since going gluten-free. I’m always looking for new and exciting ways to dress them up and show them off. I think that’s the one thing I love the most about potatoes–their versatility.

Potato Leek Gratin: This creamy spring side dish is loaded with cheese and topped with a toasted walnut crumble.

As I mentioned before, this Potato Leek Gratin was a direct result of one lonely leek in the veggie drawer. I’ve been trying to be better about food waste, so I made it my job to utilize the leek. I thought back to the time I made Roasted Garlic, Bacon & Chive Au Gratin Potatoes–which is absolutely amazing, by the way–and decided it was time to create another cheese-infused potato dish.

Potato Leek Gratin: This creamy spring side dish is loaded with cheese and topped with a toasted walnut crumble.

This is not your ordinary, run-of-the-mill potato gratin recipe. Yes, there’s cheese–lots of it! But what sets this side dish apart from other recipes is the buttery toasted walnut and bread crumb layer nestled on top of all those creamy potatoes.

Potato Leek Gratin

The crunchy Diamond of California walnut layer bakes up perfectly toasted and buttery–think brown butter meets toasted nuts. Mind blowing! It’s a lovely contrast of texture.

Potato Leek Gratin: This creamy spring side dish is loaded with cheese and topped with a toasted walnut crumble.

Of course I added a generous layer of cheese on top, because, duh! The salty cheese mingles with the crisp and crunchy walnut layer. You’ll want to make this Potato & Leek Gratin to go with every meal. If you’re busy during the week, this tasty side dish can be made in advance, skipping the walnut layer until you’re ready to re-heat and serve.

Potato Leek Gratin: This creamy spring side dish is loaded with cheese and topped with a toasted walnut crumble.

I like to dish this Potato Leek Gratin up as a vegetarian main dish and serve it with a simple side salad.

Potato Leek Gratin

Yield: 1 (9-inch-by-13-inch) pan

Total Time: 1 hour 45 minutes

Prep Time: 15 minutes

Cook Time: 1 hour 30 minutes

Ingredients:

Potato Leek Gratin

  • 6 large Idaho® Yukon Gold potatoes, very finely sliced
  • 4 tablespoons unsalted butter, plus more for greasing
  • 3 cloves garlic, peeled and minced
  • 2 and ¼ cups heavy cream
  • 1 large leek
  • 2 tablespoons freshly chopped thyme
  • 1 cup grated Parmesan cheese
  • Salt and pepper

Walnut Streusel

  • 1 cup finely chopped walnuts
  • 1 cup panko bread crumbs (regular or gluten-free)
  • 1 teaspoon freshly chopped thyme
  • 3 tablespoons melted butter
  • 1/2 cup grated Parmesan cheese

Directions:

  1. Preheat oven to 350 degrees F. Generously butter a 9-inch-by-13-inch casserole dish.
  2. Heat butter in a medium saucepan over medium heat. Add the garlic and cook, stirring often, until aromatic, about 2 minutes. Add the heavy cream to the pan and cook until the cream mixture comes to a low simmer, about 5 minutes. Remove from the heat and set aside.
  3. Remove the green part from the leek and slice in half. Run each half under cold water to clean out any dirt or sand. Pat dry and thinly slice.
  4. Place a layer of the potato slices in the bottom of the prepared casserole dish. Pour a thin layer of the cream mixture over the top. Sprinkle with kosher salt and black pepper. Top with a 1/3 of the sliced leeks, approximately 2 teaspoons chopped thyme, and 1/4 cup of Parmesan cheese. Repeat until all of the potatoes are used up. Top final layer with remaining cream.
  5. Cover the pan with aluminum foil and bake for 1 hour. Remove the pan from the oven and evenly sprinkle the walnut streusel over the potatoes. Bake, uncovered, for 30 minutes, or until the potatoes are tender and the streusel is golden brown. Remove the potatoes from the oven and allow them to rest for 15 minutes before serving.
  6. To make the walnut streusel, add walnuts, bread crumbs, thyme, and melted butter to the bowl. Mix to evenly coat. Fold in the Parmesan cheese and set aside.
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Potato & Leek Gratin: This creamy spring side dish is loaded with cheese and topped with a toasted walnut crumble.

Disclosure: This recipe was created in partnership with Diamond of California. All text and opinions are 100% my own. Thank you for your continued support as I work with brands I love and that make One Sweet Mess possible!

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