Gratin of Zucchini and Gruyère with Garlic-Thyme Butter
A low-carb gratin substituting potatoes with tender zucchini baked under a golden layer of Gruyère cheese and garlic-thyme butter. This french-inspired keto (keto, vegetarian) ready in about 55 minutes pairs sliced 1/4 inch thick medium zucchinis, unsalted butter, fresh thyme leaves for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 280 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.
Ingredients
- 4, sliced 1/4 inch thick medium zucchinis
- 4 tbsp unsalted butter
- 2 tsp fresh thyme leaves
- 2, minced garlic cloves
- 1 1/2 cups, grated gruyère cheese
- 1 cup heavy cream
- 1 tsp salt
- 1/2 tsp black pepper
- 1/4 cup, grated parmesan cheese
Instructions
- Step 1: Preheat oven to 375°F. In a small saucepan, melt 4 tbsp unsalted butter over medium heat. Add 2 tsp fresh thyme leaves and 2 minced garlic cloves, cooking for 1-2 minutes until fragrant. Remove from heat.
- Step 2: In a greased 9x13-inch baking dish, layer 4 sliced zucchinis evenly, seasoning with 1 tsp salt and 1/2 tsp black pepper.
- Step 3: Pour 1 cup heavy cream evenly over the zucchini slices. Sprinkle 1 1/2 cups grated Gruyère cheese over the top followed by 1/4 cup grated parmesan cheese.
- Step 4: Drizzle the garlic-thyme butter evenly over the gratin. Bake uncovered for 35-40 minutes until the top is bubbly and golden brown and the zucchini is tender when pierced with a fork.
- Step 5: Let rest 5 minutes before serving to allow the gratin to set and flavors to meld.
Equipment for this recipe
Top-rated tools to make this recipe successfully.
Frequently asked questions
How long does Gratin of Zucchini and Gruyère with Garlic-Thyme Butter 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 Gratin of Zucchini and Gruyère with Garlic-Thyme Butter?
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 unsalted butter from drying out.
Can I substitute ingredients in Gratin of Zucchini and Gruyère with Garlic-Thyme Butter?
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 Gratin of Zucchini and Gruyère with Garlic-Thyme Butter 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 Gratin of Zucchini and Gruyère with Garlic-Thyme Butter keto?
Yes — this recipe is tagged keto, vegetarian, low carb, gluten free based on its ingredient list. Always cross-check labels for packaged ingredients (sauces, broths, condiments) since formulations vary by brand.
