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Squash and zucchini gratin in a baking dish
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5 from 1 vote

Easy Zucchini and Squash Gratin

Layers of zucchini, squash, tomatoes, herbs and parmesan cheese made a delicious and easy side or lunch.
Course Side Dish
Cuisine Mediterranean
Keyword Squash gratin, zucchini sides
Prep Time 20 minutes
Cook Time 15 minutes
Total Time 35 minutes
Servings 6 servings
Calories 89kcal
Author The Seasoned Mom


  • ¾ lb. zucchini
  • ¾ lb. yellow summer squash
  • 2 tablespoons olive oil divided
  • ½ teaspoon minced garlic
  • ½ cup finely-diced onion
  • 1 cup canned unsalted crushed plum tomatoes in juice
  • 1 tablespoon fresh basil
  • 1 tablespoon fresh parsley
  • ½ teaspoon salt
  • ¼ teaspoon pepper
  • 3 tablespoons grated Parmesan cheese


  • Preheat oven to 400°F (200°C). Spray a medium-sized baking dish with cooking spray and set aside (I used a deep 5-inch by 9-inch dish, but a 7x11-inch dish or anything similar in size will work well).
  • Slice zucchini and squash into thin rounds (I like to use a mandolin to make it fast and uniform, but it’s not necessary).
  • In a large skillet, heat 1 tablespoon of olive oil over medium-high heat. Add garlic and cook (stirring constantly) for about 1 minute. Add zucchini and squash to the skillet. Stir and cook until vegetables are tender (about 5-6 minutes). Remove from heat.
  • In a small saucepan, add remaining 1 tablespoon of oil and diced onion. Cook onion over medium heat until translucent (about 2 minutes), and then add the tomatoes (with their juice) and the basil. Simmer tomatoes about 5 minutes. Stir in parsley, salt, and pepper to taste.
  • Spread half of the zucchini/squash mixture into the bottom of the prepared baking dish. Cover with half of the tomato sauce from the saucepan, and sprinkle with 1 tablespoon of grated Parmesan.
  • Add another layer with the remaining zucchini, top with the remaining sauce, and finish with the last 2 tablespoons of Parmesan.
  • Bake for 15 minutes, or until cheese is melted and the top becomes golden brown.
  • Allow dish to sit for about 10 minutes before serving.


Recipe inspired by Essentials of Classic Italian Cooking.


Calories: 89kcal | Carbohydrates: 8g | Protein: 3g | Fat: 5g | Saturated Fat: 1g | Cholesterol: 2mg | Sodium: 291mg | Potassium: 434mg | Fiber: 2g | Sugar: 5g | Vitamin A: 410IU | Vitamin C: 25.4mg | Calcium: 62mg | Iron: 1mg