There’s something so comforting about a bubbling dish of zucchini gratin with yellow squash coming out of the oven. The golden, crunchy topping gives way to tender slices of summer squash, all bathed in a luscious, creamy sauce. It’s simple enough for a weeknight dinner but elegant enough to take center stage on a holiday table. Whether you’re trying to use up a garden bounty or looking for a side dish that everyone at the table will rave about, this recipe delivers.

This zucchini gratin with yellow squash isn’t just delicious; it’s also flexible. You can make it ahead, tweak it to suit your pantry, or even turn it into a main dish with a few added ingredients. Let’s break down everything you need to know to make this creamy, cheesy, and absolutely irresistible gratin.

Why You’ll Love This Zucchini Gratin with Yellow Squash

This isn’t your average vegetable side dish. This gratin manages to be hearty without feeling heavy and decadent without requiring hours in the kitchen.

Key Benefits

• Incredibly Creamy and Cheesy: The sauce clings to every slice of zucchini and squash, giving you that perfect bite every time.

• A Versatile Side Dish: It pairs beautifully with roasted chicken, grilled fish, or even a simple green salad for a lighter meal.

• Easy to Make: No complicated steps or fancy equipment needed. If you can slice vegetables and stir together a sauce, you’re golden.

• Perfect for Any Occasion: From weeknight dinners to special gatherings, this dish feels right at home on any table.

Suitable For

This gratin is ideal for:

• Family Dinners: Kids and adults alike will love the creamy, cheesy layers.

• Holidays and Special Occasions: It’s an elegant way to serve up humble zucchini and squash.

• Vegetarian Diets: This dish is meat-free yet hearty enough to satisfy.

• Beginner Cooks: The steps are straightforward and forgiving, making it a great starting point if you’re new to gratins.

Ingredients for Zucchini Gratin with Yellow Squash

The beauty of this recipe is that it uses simple ingredients to create something extraordinary. Here’s what you’ll need.

Core Ingredients

• Zucchini and Yellow Squash: About two medium of each. Look for firm, blemish-free vegetables with shiny skin.

• Heavy Cream or Half-and-Half: This is the base of your creamy sauce. Half-and-half works if you prefer a lighter version.

• Gruyère Cheese: Nutty and melty, Gruyère adds depth. Mozzarella or a Parmesan blend also work beautifully.

• Garlic: Just two cloves, minced, for a subtle flavor boost.

• Breadcrumbs (Panko Preferred): For that irresistible crunchy topping.

• Butter: To bind the breadcrumbs and create a golden crust.

• Fresh Thyme or Italian Herbs: For a hint of earthiness.

• Salt and Freshly Ground Black Pepper: Don’t skip seasoning—it’s key to bringing out the flavor.

• Optional Parmesan: A sprinkle on top takes this gratin to the next level.

Substitutions and Tips

• Dairy-Free Option: Use coconut milk or cashew cream in place of heavy cream, and swap in your favorite vegan cheese.

• Gluten-Free Option: Replace panko with gluten-free breadcrumbs or crushed gluten-free crackers.

• Cheese Variations: Fontina, sharp cheddar, or even a bit of blue cheese can add a different twist.

• Extra Veggies: Thinly sliced onions or shallots layered with the squash bring natural sweetness.

The Best Cheese for Zucchini Gratin

When it comes to gratins, cheese isn’t just an ingredient—it’s the star. Gruyère is the traditional choice thanks to its smooth melting quality and nutty flavor, which complements the mild squash beautifully.

But don’t worry if you can’t find Gruyère. Sharp cheddar gives a punchier taste, mozzarella melts like a dream, and Fontina adds a luxurious creaminess. A mix of cheeses works wonders too—try half Gruyère and half Parmesan for the best of both worlds.

Kitchen Tools You’ll Need

Before you begin, make sure you have the right tools on hand. This isn’t a fussy recipe, but having the basics will make it a breeze.

Must-Have Tools

• Sharp Knife or Mandoline Slicer: For even, thin slices of zucchini and squash.

• Medium Baking Dish: An 8×8 or 9×13 dish works well depending on how thick you want your layers.

• Mixing Bowls: For the creamy sauce and breadcrumb topping.

• Whisk: To blend the sauce ingredients smoothly.

Nice-to-Have Tools

• Microplane or Box Grater: Perfect for finely grating cheese.

• Food Processor: Speeds up slicing if you’re making a larger batch.

How to Make Zucchini Gratin with Yellow Squash (Step by Step)

This zucchini gratin with yellow squash is pure comfort food made simple. Whether you’re cooking for a family dinner or prepping ahead for a holiday meal, these step-by-step instructions will guide you with confidence. By the end, you’ll have a dish that’s as beautiful as it is delicious—golden, bubbly, and packed with flavor.

Step 1: Preheat and Prepare

Start by preheating your oven to 375°F (190°C). This gives your gratin a head start for even baking and that perfectly golden crust. Butter or lightly grease your baking dish—an 8×8 or 9×13 works well depending on how thick you like your layers.

Pro Tip: Use unsalted butter so you can control the saltiness of your finished dish.

Step 2: Slice the Vegetables

The key to a great gratin is evenly sliced vegetables. Cut your zucchini and yellow squash into 1/8-inch rounds. A mandoline slicer is your best friend here, but a sharp knife works just as well with a little patience.

Why thin slices matter: Uniform slices cook evenly, preventing undercooked centers or mushy edges.

Step 3: Make the Creamy Sauce

In a medium mixing bowl, whisk together the heavy cream (or half-and-half), minced garlic, grated Gruyère cheese, herbs, salt, and freshly ground black pepper. This sauce is what transforms simple squash into a decadent, silky side dish.

Optional twist: Stir in a teaspoon of Dijon mustard for a subtle tang that brightens the richness.

Step 4: Assemble the Gratin

Here’s where the magic begins:

• Arrange half the zucchini and yellow squash slices in an overlapping pattern in your prepared baking dish.

• Pour half of the creamy cheese sauce evenly over the vegetables.

• Repeat with the remaining squash and sauce, making sure everything is coated.

Make it pretty: For a special occasion, arrange the slices in a spiral pattern or alternating colors for a visually stunning dish.

Step 5: Add the Topping

In a small bowl, combine the panko breadcrumbs with melted butter until evenly coated. Sprinkle this mixture over the top of your gratin. For an extra layer of flavor, add a light dusting of grated Parmesan cheese.

Why panko? Panko gives you a lighter, crispier topping compared to regular breadcrumbs.

Step 6: Bake to Golden Perfection

Place your gratin in the preheated oven and bake for 35 to 40 minutes. The vegetables should be tender when pierced with a knife, and the topping should be golden brown and crisp.

Finishing touch: If the topping isn’t as golden as you’d like, pop it under the broiler for 1 to 2 minutes—but keep a close eye to prevent burning.

Tips for Success

Perfecting this zucchini gratin is easier than you might think, but these extra tips will help you get it right every time:

• Prevent a watery gratin: Salt the sliced zucchini and squash, let them sit for 10 minutes, and then pat dry with paper towels. This step draws out excess moisture.

• Use fresh herbs: If possible, opt for fresh thyme or basil for a brighter flavor.

• Make it ahead: Assemble the gratin up to a day in advance, cover tightly with foil, and refrigerate. Bake just before serving.

• Customize the flavor: Add caramelized onions or roasted garlic for a deeper, sweeter taste.

How to Store Zucchini Gratin with Yellow Squash

This dish reheats beautifully, making it a smart choice for leftovers.

At Room Temperature

After baking, let the gratin cool slightly before serving. It can sit at room temperature for up to 2 hours if you’re serving buffet-style.

In the Refrigerator

Store any leftovers in an airtight container in the fridge for up to 3 days. To reheat, place in a 350°F oven for 10–15 minutes to revive the crispy topping.

Freezing Tips

You can freeze the unbaked gratin for up to 2 months. Assemble the dish without the breadcrumb topping, wrap it tightly in plastic wrap and foil, and freeze. When ready to bake, add the topping and cook straight from frozen, adding about 15 minutes to the bake time.

Frequently Asked Questions (FAQs)

Can I make zucchini gratin ahead of time?

Absolutely. Assemble it fully, cover, and refrigerate for up to 24 hours. Bake just before serving for the freshest result.

How do I stop zucchini gratin from being watery?

Salt and drain the squash slices before layering to remove excess moisture. Also, avoid overpacking the layers, which can trap water.

What other vegetables can I add?

Thinly sliced potatoes, sweet potatoes, or even eggplant work beautifully layered with the zucchini and yellow squash.

Is there a way to make this vegan?

Yes. Swap heavy cream for coconut milk or cashew cream and use vegan cheese alternatives. You can also top with crushed nuts or gluten-free breadcrumbs for a crunchy finish.

Related Recipes You’ll Love

If you loved this zucchini gratin with yellow squash, try these other savory and cheesy favorites:

• Scalloped Potatoes and Ham – Creamy, cheesy, and perfect for holidays.

• Garlic Butter Chicken Pasta – A hearty pasta dish with rich garlic butter flavor.

• Spinach and Cheese Casserole – Another delicious, vegetable-forward bake.

• Keto Sloppy Joe Casserole – A low-carb comfort food option.

• Cheesy Rotini with Garlic Butter Beef – For when you want cheesy goodness in pasta form.

Conclusion

This zucchini gratin with yellow squash proves that simple ingredients can create an unforgettable dish. With its creamy, cheesy layers and crispy golden topping, it’s sure to become a favorite in your kitchen. Whether you serve it warm from the oven or enjoy leftovers the next day, every bite is pure comfort.

Try it for your next dinner and watch it disappear faster than you expect. And don’t forget to come back and let me know how it turned out.

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