Cheesy Zucchini Gratin is one of those magical summer dishes that feels indulgent yet effortless. With tender zucchini slices layered into a creamy garlic-infused sauce and blanketed in bubbling melted cheese, this bake hits all the right notes. Whether you’re serving it alongside grilled meats or letting it shine as a vegetarian main, it’s a warm-weather comfort food that always pleases.
In this post, I’ll guide you through each step of the recipe while weaving in my favorite serving tips, tools, and even other zucchini favorites from the blog. And hey—if you’re loving this kind of kitchen inspiration, be sure to follow me over on Pinterest for more weeknight favorites and seasonal sides!
A Family Favorite Born From Abundance
Cheesy Zucchini Gratin became a staple in our home the summer our garden went wild with zucchini. Every few days, I’d find a few more tucked beneath the leaves, almost begging to be transformed into something delicious. That’s how this recipe was born—equal parts necessity and comfort.
Unlike many gratins that feel heavy or overly rich, this one keeps things light with whole milk and a blend of Gruyère and Parmesan. The zucchini gets just soft enough to melt in your mouth while still holding its structure, and the garlicky white sauce wraps everything in velvety flavor. I’ve made it dozens of times—sometimes as a side, often as the main event with a leafy salad and crusty bread.
Not only is this Cheesy Zucchini Gratin ideal for family dinners, but it also makes an excellent contribution to potlucks or holiday tables. It’s a flexible, satisfying recipe that works with whatever herbs and cheeses you’ve got on hand.
Why This Zucchini Gratin Stands Out
What makes this version of Cheesy Zucchini Gratin so special is its simplicity paired with incredible depth of flavor. You don’t need a fancy mandoline or hard-to-find cheeses. Just fresh zucchini, a touch of garlic, and a few pantry staples.
The sauce comes together in one skillet, and the baking process is forgiving. Even if your layers aren’t perfect, they’ll settle beautifully during cooking, and the gratin will emerge from the oven golden and bubbling. Recipes like this prove that comfort food doesn’t have to be complicated.
For more zucchini inspiration, you’ll love these Layered Zucchini Ricotta Melts with Marinara or this crispy Zucchini Fritters Recipe—both quick summer favorites!
Ingredients & Preparation
Ingredient Breakdown
To make the perfect Cheesy Zucchini Gratin, here’s what you’ll need:
| Ingredient | Quantity |
|---|---|
| Butter (plus more for pan) | 2 tablespoons |
| Garlic, minced | 4 cloves |
| All-purpose flour | 2 tablespoons |
| Whole milk | 1 ½ cups |
| Gruyère cheese, shredded | 2 cups, divided |
| Parmesan, freshly grated | ½ cup |
| Kosher salt & black pepper | To taste |
| Zucchini (medium) | 4–5, thinly sliced |
| Italian seasoning | 2 teaspoons |
| Fresh thyme | 2 teaspoons, chopped |
This list may look simple, but the combination of melty cheese, aromatic garlic, and earthy zucchini delivers full-on comfort and flavor. I often substitute mozzarella for Gruyère when I’m short on ingredients—it still turns out amazing.
Tools You’ll Need & Substitutions
You don’t need anything fancy to make this Cheesy Zucchini Gratin. A large skillet for the sauce, a medium baking dish, and a sharp knife are enough.
Helpful tools:
-
Mandoline slicer (for even zucchini slices)
-
Whisk (for a smooth sauce)
-
Casserole dish (9×13 or similar)
Substitutions & Add-ins:
-
Cheese: Mozzarella, cheddar, or fontina can replace Gruyère.
-
Milk: Whole milk is best, but 2% works.
-
Herbs: Swap thyme for rosemary or basil.
-
Add-ins: Add sautéed mushrooms or thin tomato slices between the zucchini layers.
You can also use this gratin base to experiment—similar to how I riffed on flavors with my Rustic Roasted Vegetable Bake with Cannellini Beans.
Cooking Instructions & Tips
Step-by-Step Cooking Method
-
Preheat & Prep: Preheat oven to 375°F (190°C) and butter a medium-sized baking dish.
-
Make Sauce: Melt butter in a skillet. Add garlic and sauté for about a minute. Whisk in flour and cook until golden and bubbling.
-
Thicken: Pour in milk slowly, stirring constantly. Simmer until slightly thickened.
-
Cheesy Base: Turn off heat and stir in 1 cup of Gruyère and all of the Parmesan. Season with salt and pepper.
-
Layer: In the buttered dish, add a single layer of zucchini. Pour one-third of the cream mixture, sprinkle with cheese and thyme.
-
Repeat: Repeat for two more layers, alternating zucchini, cream, cheese, and seasonings.
-
Bake: Bake uncovered for 20–25 minutes, or until golden and bubbling.
Tips and Tricks to Perfect It
-
Thin slices cook best. Use a mandoline if you have one.
-
Salt the zucchini slightly before layering if your squash seems especially watery.
-
Don’t skip the thyme! Fresh thyme brings bright flavor that balances the rich sauce.
-
Want it crispier? Broil for the last 1–2 minutes of baking.
Serve this with a vibrant side like Spinach and Artichoke Wonton Cups or pair it with a green salad to keep things fresh.
Serving, Storing & Pairing
What to Serve With Cheesy Zucchini Gratin
This dish is incredibly versatile—it can be the star or play a delicious supporting role. Here are a few of my favorite ways to serve it:
-
Alongside roasted chicken or grilled fish.
-
As a vegetarian main with crusty bread and salad.
-
With Balsamic Fig Chicken Thighs with Onions and Thyme for a dinner that’s both elegant and cozy.
It also pairs beautifully with red or white wine. I often go with a chilled glass of Pinot Grigio or a light red like Pinot Noir.
And if you’re looking for more hearty vegetarian mains, try the Spinach Zucchini Chickpea Bake—it’s just as satisfying!
How to Store and Reheat
-
Store: Cool completely, then refrigerate in an airtight container for up to 4 days.
-
Reheat: Warm individual portions in the microwave or reheat the whole dish in a 350°F oven until hot.
-
Freezing not recommended as the zucchini may become watery.
FAQ Section
Can I make this ahead of time?
Yes! Assemble it up to a day in advance and refrigerate. Bake when ready to serve.
What other vegetables work in this gratin?
Thinly sliced potatoes, summer squash, or eggplant all work beautifully.
Is it keto-friendly?
Yes, it’s naturally low in carbs—just be mindful of the flour. You can substitute almond flour for a keto version.
Can I use plant-based milk or cheese?
Definitely. Go with unsweetened almond or oat milk and vegan cheese alternatives.
How do I make it more filling?
Add cooked quinoa or shredded rotisserie chicken between the layers.
Conclusion
This Cheesy Zucchini Gratin has a way of turning simple summer ingredients into something that feels extra special. It’s cheesy, savory, comforting—and made with love every time. Whether you serve it fresh from the oven or warmed up the next day, this dish never disappoints.
Looking for more ways to enjoy zucchini and cheese? Check out my Crispy Zucchini Fritters Recipe or creamy Chicken Scampi Pasta.
If you try this Cheesy Zucchini Gratin, let me know in the comments! I’d love to hear how it turned out for you. Don’t forget to rate the recipe and share it on Pinterest so more home cooks can enjoy it!
Print
Cheesy Zucchini Gratin
- Total Time: 30
- Yield: 8 servings
- Diet: Vegetarian
Description
Cheesy Zucchini Gratin is a creamy, garlicky, and golden-baked summer side dish. Thinly sliced zucchini layers are smothered in a rich Gruyère-Parmesan sauce and topped with herbs for a simple, indulgent casserole that’s quick to prepare and even better fresh from the oven.
Ingredients
• 2 tablespoons butter (plus more for buttering pan)
• 4 cloves garlic, minced
• 2 tablespoons all-purpose flour
• 1 1/2 cups whole milk
• 2 cups shredded Gruyère cheese (or mozzarella), divided
• 1/2 cup freshly grated Parmesan
• 1/4 teaspoon kosher salt and freshly ground black pepper, to taste
• 4–5 medium zucchini, thinly sliced
• 2 teaspoons Italian seasoning
• 2 teaspoons freshly chopped thyme
Instructions
1. Preheat oven to 375°F (190°C) and butter a medium baking dish.
2. In a large pan over medium heat, melt butter. Add garlic and cook until fragrant, about 1 minute.
3. Whisk in flour and cook until golden and bubbling, about 1 minute.
4. Slowly add milk, stirring constantly. Simmer until slightly thickened, about 1 minute.
5. Turn off heat. Stir in 1 cup Gruyère and all Parmesan. Season with salt and pepper.
6. Layer zucchini slices in baking dish. Pour one-third of cheese sauce over top. Sprinkle some Gruyère and thyme.
7. Repeat two more layers with remaining zucchini, sauce, cheese, and seasonings.
8. Bake uncovered for 20–25 minutes until bubbly and golden.
9. Garnish with fresh thyme and serve immediately.
Notes
– Mozzarella can substitute for Gruyère if preferred.
– To make keto-friendly, replace flour with almond flour.
– For added flavor, sauté mushrooms and layer between zucchini.
– Not recommended for freezing; zucchini may become watery.
– Use a mandoline slicer for thin, even zucchini layers.
- Prep Time: 10
- Cook Time: 20
- Method: Baking
- Cuisine: American