Zucchini and Gruyère Gratin with Thyme

By AislePrompt Test Kitchen · Reviewed by AislePrompt Editorial · ·

A creamy, cheesy zucchini gratin baked with fresh thyme and Gruyère cheese, making a perfect low-carb side dish rich in flavor and fats. This french-inspired keto (vegetarian, low carb) ready in about 55 minutes pairs grated gruyère cheese, heavy cream, minced garlic cloves for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 320 calories and feeds 6, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Prep: 15 min Cook: 40 min Serves 6 French cuisine 320 cal/serving
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Ingredients

Instructions

  1. Step 1: Preheat oven to 375°F. Grease a 9x9-inch baking dish with 2 tbsp unsalted butter.
  2. Step 2: In a bowl, toss 4 sliced medium zucchinis with 1 tsp salt, 1/2 tsp black pepper, 2 minced garlic cloves, 1 tbsp fresh thyme leaves, and 1/8 tsp freshly grated nutmeg.
  3. Step 3: Layer half of the zucchini slices evenly in the baking dish. Sprinkle 1 cup grated Gruyère cheese over the first layer.
  4. Step 4: Add remaining zucchini slices on top, then pour 1 cup heavy cream evenly over the layers. Top with remaining 1 cup Gruyère cheese.
  5. Step 5: Bake uncovered for 35-40 minutes until the gratin is bubbling and the top is golden brown. Let rest for 5 minutes before serving.

Equipment for this recipe

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Frequently asked questions

How long does Zucchini and Gruyère Gratin with Thyme take to make?

Total time is about 55 minutes (15 min prep + 40 min cook). Most home cooks find this fits comfortably into a weeknight; double the batch on Sunday for two dinners.

How do I store leftover Zucchini and Gruyère Gratin with Thyme?

Cool to room temperature within 2 hours, then store in an airtight container in the fridge for up to 4 days. Reheat covered in a 350°F oven for 10-12 minutes, or microwave at 70% power in 60-second bursts to keep grated gruyère cheese from drying out.

Can I substitute ingredients in Zucchini and Gruyère Gratin with Thyme?

Yes — most ingredients in this recipe have flexible swaps. For oil, use any neutral high-smoke-point oil (avocado, grapeseed, refined coconut). For aromatics, dried herbs at ⅓ the volume of fresh work in a pinch. The full ingredient list is shoppable on Instacart so you can see substitutes in real time.

How do I scale Zucchini and Gruyère Gratin with Thyme for a different number of people?

The recipe is written for 6 servings. Multiply each ingredient by (your serving target / 6). Cook time stays roughly the same up to 2x; for 3-4x batches, switch from a skillet to a sheet pan or stockpot so the food isn't crowded — overcrowding steams instead of browns.

Is Zucchini and Gruyère Gratin with Thyme vegetarian?

Yes — this recipe is tagged vegetarian, low carb based on its ingredient list. Always cross-check labels for packaged ingredients (sauces, broths, condiments) since formulations vary by brand.

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