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Cod and Potato Gratin with Leeks

If you are looking to serve a fish and potato dinner then this recipe for Cod and Potato Gratin has to be among one of the easiest recipes in the world to make. Cod and Potato Gratin with Leeks
Not only is the preparation super simple, but so is the clean up! Since everything gets cooked right in individual-sized baking dishes (or one big gratin pan, if you prefer), you don’t even need to dirty a single pot or pan. The recipe takes an hour to bake, but you’ll spend less than 30 minutes of hands-on time preparing it, making it a perfect weeknight dinner option. However, it is absolutely special enough to serve to guests too!

Williams Sonoma CookbookWhat Makes This Recipe for Cod and Potato Gratin “Clean”?

You can find a jillion potato gratin recipes with cheese (LOTS of cheese…and cream too!) online, but you won’t find a lot of recipes that include the words “potato” and “gratin” that are also dairy free. In fact, some might even argue that my Cod and Potato Gratin recipe isn’t really even a gratin since it doesn’t have a cheese or breadcrumb topping.  However, I adapted the recipe from the Williams-Sonoma One Pot of the Day cookbook (a great cookbook by the way) and their version had neither breadcrumbs or cheese and was still called a gratin. So that’s what I am calling mine too 😉 The biggest difference between the Williams-Sonoma version and mine is that I use cashew cream instead of dairy cream. You really can’t taste the difference though. Honestly.

Dairy Free Potato Gratin

Everything Always Tastes Better When Served in Individual-Sized Baking Dishes

If you have kids at home with picky palates (especially ones who claim they don’t like fish!) you might be surprised that they actually eat and like this recipe if served in an individual-sized casserole dish. While I would like to take full credit if they do like the recipe, the individual-sized casserole dish would deserve almost equal credit. That’s because just about whatever you serve in an individual-sized casseroled dish is going to look so much more attractive than if the recipe were to be spooned out onto a plate. And the old saying that we eat with our eyes first really is true—it’s especially true with kids! If you follow Clean Cuisine you have probably seen me use these casserole dishes before—most frequently in these two recipes:

****Note: Individual-sized casserole dishes can be purchased on Amazon***

For those of you with food allergies and food sensitivities, it’s helpful to know the recipe for Cod and Potato Gratin meet the following dietary restrictions:

Grain Free / Gluten Free /Egg Free / Dairy Free/ Bean Free/ 


Cod and Potato Gratin with Leeks (Dairy Free)

Cod and Potato Gratin with Leeks is easy an easy enough recipe for weeknight dinners but it’s also special enough to serve to guests. And nobody will ever guess it’s dairy free!

Save Recipe
  • Prep Time: 25 minutes
  • Cook Time: 60 minutes
  • Total Time: 1 hour 25 minutes
  • Yield: 6 1x


  • 3/4 cup raw cashews, preferably soaked 1 to 2 hours
  • 1 cup minus 2 tablespoons water
  • 2 tablespoons lemon juice
  • 1/2 teaspoon Dijon mustard
  • 1/2 teaspoon raw honey
  • 1/8 teaspoon Himalayan pink salt, plus more to taste
  • White pepper, to taste
  • 1 1/2 pounds white potatoes
  • 1 leek, white and green parts, halved
  • 1 pound wild cod or haddock (or other firm white fish), thickly sliced on the diagonal
  • Sliced scallions, for garnish, optional


  1. Preheat oven to 375 degrees. Lightly oil the bottom and sides of six 8-ounce individual-sized baking dishes or a 13-inch oval gratin pan.
  2. To a high speed blender, add the cashews, water, lemon juice, Dijon mustard, honey and 1/8 teaspoon of the salt.
  3. Process on high speed until smooth and creamy. Set cashew cream aside.
  4. Cut the potatoes crosswise into thin, uniform slices. Cut the leeks crosswise into slices about twice as thick as the potatoes.
  5. Season the fish lightly with salt.
  6. Spread half of the potatoes among the six individual-sized baking dishes, overlapping to cover the bottom.
  7. Season potatoes lightly with salt and pepper. Scatter half of the leeks over the potatoes, then arrange the fish slices over the leeks in a single layer, overlapping the slices as necessary.
  8. Top with the remaining potatoes. Season with salt and pepper to taste. Pour the cashew cream evenly over the layers (Note: if using individual-sized baking dishes you will use about 1/3 cup of cashew cream per dish.)
  9. Bake for 40 minutes.
  10. Remove from the oven and spoon some of the cooking liquid over the top of the gratin to moisten the potatoes.
  11. Continue to bake until the tom layer of potatoes is tender when pierced with a sharp knife, about 10 to 15 additional minutes.
  12. Let stand for 10-15 minutes, garnish with scallions (optional) and serve.

Last Step! If you loved our recipe, leave us a review below. This helps future recipe makers and ensures continued high-quality recipes for years to come!

© 2024 clean cuisine Recipe by:

Ivy Larson

In 2010, Clean Cuisine was launched because Ivy Larson wanted to share her anti-inflammatory lifestyle and delicious recipes using ingredients in their most natural and nutrient-rich state. In 2020, Ivy passed the website to Aimee and Madison. Since then, they have been adding new recipes and nutrition posts while updating old recipes and articles. Thanks for visiting Clean Cuisine!

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