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A freshly baked zucchini gratin in a casserole dish with a golden, crispy cheese topping.

Classic Zucchini Gratin

A rich and creamy zucchini gratin topped with melted cheese and a crispy golden crust, perfect as a comforting side dish.
Prep Time 20 minutes
Cook Time 30 minutes
Total Time 50 minutes
Course Side Dish
Cuisine French
Servings 4 servings
Calories 380 kcal

Equipment

  • Baking Dish
  • Large skillet
  • Mixing bowl

Ingredients
  

For the Zucchini

  • 2-3 zucchini medium-sized, sliced into thin rounds
  • 1/2 tsp salt to remove moisture

For the Creamy Sauce

  • 2 tbsp butter melted
  • 2 cloves garlic minced
  • 1 cup heavy cream
  • 1/2 tsp black pepper or to taste
  • 1/4 tsp nutmeg optional
  • 1 egg beaten (optional, for thickening)
  • 1/2 cup Gruyère or Parmesan cheese grated

For Topping

  • 1/2 cup Gruyère or Parmesan cheese grated
  • 1/2 cup breadcrumbs optional, for a crispy topping

Instructions
 

  • Rinse and slice the zucchini into thin rounds (about ⅛ to ¼ inch thick).
  • Sprinkle salt over the zucchini slices and let them sit for 15–20 minutes to draw out moisture.
  • Pat the zucchini dry with a clean kitchen towel or paper towels.
  • Preheat oven to 375°F (190°C) and grease a baking dish with butter or oil.
  • In a large skillet, melt butter over medium heat. Add minced garlic and sauté for 30 seconds until fragrant.
  • Pour in heavy cream and stir to combine. Add black pepper, salt, and nutmeg.
  • For a thicker sauce, whisk in a beaten egg while stirring constantly.
  • Gradually stir in ½ cup of grated Gruyère or Parmesan cheese until melted and smooth.
  • Layer the zucchini slices in an overlapping pattern in the prepared baking dish.
  • Pour the creamy sauce over the zucchini, spreading it evenly to coat all slices.
  • Sprinkle the remaining ½ cup of cheese on top. If desired, add ½ cup of breadcrumbs for extra crunch.
  • Bake uncovered for 25–30 minutes until the top is bubbly and golden brown.
  • For extra crispiness, broil on high for the last 2–3 minutes.
  • Let the gratin rest for 5–10 minutes before serving to allow the sauce to thicken.

Notes

For a different flavor, try using mozzarella, cheddar, or goat cheese in place of Gruyère.
Keyword Cheesy Casserole, Gratin, Zucchini