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Close up of keto zucchini gratin with a wood spoon lifting some up
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5 from 6 votes

Zucchini Gratin

Zucchini Gratin is a delicious, creamy, cheesy casserole and a great way to use up some of that summer zucchini crop. This recipe is made grain-free making it gluten free and keto friendly. It’s an easy, tasty dish that the whole family will enjoy.
Prep Time10 mins
Cook Time20 mins
Total Time30 mins
Course: Side Dish
Cuisine: American, Gluten Free, Low Carb, Vegetarian
Servings: 6
Calories: 420kcal


Zucchini Gratin

  • 1 tablespoon unsalted butter
  • 2 pounds zucchini * sliced into 1/4-inch rounds, from about 4 medium zucchini
  • 1 shallot * finely diced
  • 2 cloves garlic * minced
  • 1 cup heavy whipping cream
  • 1 teaspoon salt
  • 1/2 teaspoon pepper
  • 1/2 cup Parmesan cheese
  • 1 cup Gruyere cheese * divided

Almond Flour Crumbs


Zucchini Casserole

  • Grease a large casserole dish using a small amount of butter or cooking spray and preheat oven to 400°F.
  • Place a layer of zucchini rounds into the bottom of the casserole dish, overlapping them slightly. Set aside the remaining zucchini.
  • Heat a large skillet over medium-high heat and add the butter. Once melted, add the shallot and garlic and cook for 2-3 minutes, stirring frequently, until softened.
  • Carefully pour in the heavy cream and raise the heat to high. Bring to a boil and cook another minute or so, until thickened slightly.
  • Remove the pan from the heat and stir in the Parmesan cheese and 1/2 cup of the Gruyere cheese.
  • Pour half of the cheese sauce over the zucchini in the casserole dish, then add a second layer of zucchini and the remaining sauce.

Almond Flour Crumbs

  • Combine the almond flour and melted butter in a small bowl with a fork until crumbs form. Using your fingers, break the crumbs up over the casserole and add the remaining Gruyere cheese.
  • Bake, uncovered, for approximately 20 minutes, or until the almond flour crumbs and cheese are light brown and the zucchini is just fork-tender.



Alternative Gratin Toppings

  1. Use only the Gruyere cheese.
  2. Make a pistachio topping (see this in the recipe for Brussels Sprouts Gratin - it's SO good!).
  3. Use crushed pork rinds.
  4. If you’re not low carb, you can use regular or gluten free breadcrumbs.

How to Store Leftovers

Store leftovers in an air-tight container in the refrigerator. Use within 3 days.
** Nutritional information is an estimate and may vary.


Serving: 1g | Calories: 420kcal | Carbohydrates: 10g | Protein: 15g | Fat: 37g | Saturated Fat: 19g | Cholesterol: 99mg | Sodium: 624mg | Potassium: 464mg | Fiber: 3g | Sugar: 5g | Vitamin A: 1334IU | Vitamin C: 28mg | Calcium: 402mg | Iron: 1mg