Recipes | Side Dishes

Low FODMAP Potato Cheese Gratin with Mushrooms


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Low FODMAP Potato Cheese Gratin with Mushrooms

This Low FODMAP Potato Cheese Gratin with Mushrooms is comfort food in a casserole dish! Potatoes, cream, melted, creamy Gruyere cheese, garlic-infused oil sautéed mushrooms  – all baked until golden brown and bubbly.

Absolute perfection on a cold winter’s night, or how about as a side dish to your Easter ham or Passover lamb? Sublime!

Low FODMAP Potato Cheese Gratin with Mushrooms

But don’t count this dish out on a weeknight with a simple roast chicken! And it would not be out of place alongside Thanksgiving turkey.

Slice Them Thinly

The dish uses a whopping 2-pounds (910 g) of potatoes. You could use starchy russet potatoes as we did in our Classic Potato Gratin casserole, or use Yukon Gold potatoes as we suggest here.

Whichever potatoes you use, make sure to slice them very thinly, which is most easily accomplished with a mandoline or a food processor fitted with a slicing blade.

closeup low FODMAP potato cheese gratin with mushrooms on green plate
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Dairy & The Low FODMAP Diet

The low FODMAP diet is NOT a dairy-free diet, but it is lowered in lactose. If you cannot find lactose-free half-and-half, we have an article for you that shows you how to make your own lactose-free dairy.

And since you are a cheese lover, be sure to see our round-up of our most beloved, cheesy recipes.

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low FODMAP Potato Cheese Gratin with Mushrooms in casserole dish and on green plate
5 from 4 votes

Low FODMAP Potato Cheese Gratin with Mushrooms

Looking for a comfort-food potato gratin - with a twist? Ours has low FODMAP oyster mushrooms, too.

Makes: 14 Servings
Prep Time: 15 minutes
Cook Time: 40 minutes
Total Time: 55 minutes
Author: Dédé Wilson


  • 3 tablespoons Garlic-Infused Oil, made with olive oil, or purchased equivalent, divided
  • 6- ounces (170 g) cleaned oyster mushrooms, chopped
  • 2 pounds (910 g) yukon gold potatoes, peeled
  • 3 cups (720 ml) lactose-free half-and-half, at room temperature
  • 1 teaspoon kosher salt
  • Freshly ground black pepper
  • 1/4 pound (115 g) Gruyere cheese, grated


  1. Position rack in middle of oven. Preheat the oven to 400°F/200°C. Use 1 tablespoon of Garlic-Infused Oil to coat the inside of a 3-quart (2.8 L) shallow casserole dish; set aside.
  2. Heat remaining 2 tablespoons of oil in a large sautepan (I use a 3-quart/2.8 L) and heat over medium heat. Add chopped mushrooms and saute until softened, just a few minutes, then remove from heat. Set aside.

  3. Cut the potatoes very thinly into 1/8-inch (3 mm) rounds using a very sharp knife, a mandoline, or the slicing disc of a food processor.
  4. Add the potatoes to the saucepan then add the half-and-half, salt and generous amount of pepper. Bring to a vigorous simmer over medium heat, shaking the pan occasionally, and simmer for 3 minutes.

  5. Carefully scoop and pour the mixture into prepared casserole dish. Gently coax the potatoes, mushrooms and liquid into an even layer. Sprinkle the cheese evenly over the top.

  6. Bake for about 35 to 45 minutes or until the potatoes are tender when pierced with a knife and the top is golden and bubbling. The mixture might look a little loose, but don’t worry, it will firm up upon cooling. Place casserole on a rack and cool for at least 15 minutes to allow the gratin to achieve its maximum potato perfection. Serve warm or even at room temperature.


If You Can Tolerate

  • Lactose: if you have passed the lactose challenge, feel free to use conventional half-and-half in the same amount.
Course: Dinner, Side Dish
Cuisine: American


Calories: 175kcal | Carbohydrates: 14g | Protein: 5g | Fat: 11g | Sodium: 168mg | Fiber: 2g | Sugar: 1g

All nutritional information is based on third-party calculations and should be considered estimates. Actual nutritional content will vary with brands used, measuring methods, portion sizes and more. For a more detailed explanation, please read our article Understanding The Nutrition Panel Within Our Recipes.