Provençal Summer Zucchini Gratin with Gruyère and Thyme

🌍 Cuisine: French
🏷️ Category: Side Dish
⏱️ Prep: 25 minutes
🍳 Cook: 45 minutes
👥 Serves: 6 servings

📝 About This Recipe

This classic Gratin de Courgettes captures the essence of a sun-drenched French summer, transforming humble zucchini into a sophisticated, soul-warming side dish. Slices of tender zucchini are bathed in a velvety, nutmeg-scented béchamel and topped with a golden crust of nutty Gruyère cheese and herbed breadcrumbs. It is a masterclass in French country cooking, balancing the lightness of seasonal vegetables with the luxurious indulgence of a traditional gratin.

🥗 Ingredients

The Vegetables

  • 1.5 kg Zucchini (sliced into 1/2 cm rounds)
  • 1 large Yellow Onion (finely diced)
  • 3 cloves Garlic (minced)
  • 2 tablespoons Olive Oil (extra virgin)
  • 1 teaspoon Fine Sea Salt (for sweating the zucchini)

The Béchamel Sauce

  • 40 grams Unsalted Butter
  • 40 grams All-purpose Flour
  • 500 ml Whole Milk (warmed slightly)
  • 1/4 teaspoon Nutmeg (freshly grated)
  • 1/2 teaspoon Black Pepper (freshly cracked)

The Topping & Herbs

  • 150 grams Gruyère Cheese (freshly grated)
  • 30 grams Parmesan Cheese (grated)
  • 1/2 cup Panko or Fresh Breadcrumbs (for texture)
  • 2 teaspoons Fresh Thyme (leaves only)
  • 1 tablespoon Fresh Parsley (finely chopped)

👨‍🍳 Instructions

  1. 1

    Preheat your oven to 200°C (400°F). Lightly grease a 9x13 inch ceramic baking dish with butter or olive oil.

  2. 2

    Place the zucchini rounds in a large colander and sprinkle with the sea salt. Let them sit for 15 minutes to draw out excess moisture; this prevents a soggy gratin.

  3. 3

    While the zucchini rests, heat olive oil in a large skillet over medium heat. Sauté the diced onions until translucent and soft, about 5-7 minutes. Add the minced garlic and cook for another 60 seconds until fragrant.

  4. 4

    Pat the zucchini rounds thoroughly dry with a clean kitchen towel or paper towels. Add them to the skillet with the onions and sauté for 5 minutes just to soften slightly. Remove from heat.

  5. 5

    In a medium saucepan, melt the butter over medium heat. Whisk in the flour and cook for 2 minutes to create a roux, ensuring it doesn't brown.

  6. 6

    Gradually pour in the warm milk while whisking constantly. Continue to cook and whisk until the sauce thickens enough to coat the back of a spoon.

  7. 7

    Remove the béchamel from heat. Stir in the nutmeg, black pepper, and half of the grated Gruyère cheese until melted and smooth.

  8. 8

    In a small bowl, mix the breadcrumbs, Parmesan, and fresh thyme together.

  9. 9

    Transfer the zucchini and onion mixture into the prepared baking dish, spreading it out evenly.

  10. 10

    Pour the cheesy béchamel sauce over the zucchini, using a spatula to ensure it seeps into the layers.

  11. 11

    Sprinkle the remaining Gruyère over the top, followed by the herbed breadcrumb mixture.

  12. 12

    Bake in the center of the oven for 25-30 minutes, or until the sauce is bubbling vigorously and the top is a deep golden brown.

  13. 13

    Let the gratin rest for at least 10 minutes before serving. This allows the sauce to set so you get clean portions rather than a puddle.

💡 Chef's Tips

Always salt and drain your zucchini; skipping this step leads to a watery sauce. For a lighter version, you can substitute half the milk with vegetable stock, though it won't be as creamy. Use a mix of yellow squash and green zucchini for a beautiful visual contrast in the dish. If the top browns too quickly, tent the dish loosely with foil for the final 10 minutes of baking. Always grate your cheese from a block; pre-shredded cheese is coated in starch and won't melt as beautifully.

🍽️ Serving Suggestions

Serve alongside a roasted chicken (Poulet Rôti) for a quintessential French Sunday lunch. Pairs beautifully with a crisp, chilled glass of Provence Rosé or a dry Sauvignon Blanc. Accompany with a simple green salad tossed in a sharp Dijon vinaigrette to cut through the richness. Great as a vegetarian main course served with a side of crusty baguette to soak up the sauce. Leftovers are delicious the next day served at room temperature with a poached egg on top.