Summer brings an abundance of fresh, vibrant produce, and for me, zucchini and yellow squash are always at the top of the list. While they’re fantastic grilled or sautéed, sometimes you want to transform them into something truly indulgent. That’s where this Creamy Zucchini and Squash Gratin comes in. It takes simple summer vegetables and bathes them in a rich, cheesy sauce, then bakes them to golden, bubbly perfection. It’s the kind of side dish that steals the show, or even makes a delightful light main course.

Why I Love This Recipe

I’m a firm believer that vegetables can be just as comforting and decadent as any other dish, and this gratin is living proof. What makes me absolutely adore this recipe is the incredible combination of tender-crisp zucchini and squash with that luxurious, cheesy cream sauce. The subtle sweetness of the caramelized onions and garlic perfectly complements the richness of the heavy cream and the blend of Parmesan and smoked Gouda. That smoked Gouda, in particular, adds a fantastic depth of flavor that sets this gratin apart. It’s surprisingly quick to put together for such an impressive result, making it a perfect addition to any meal, from a casual weeknight dinner to a special gathering.

Ingredients

• 2 tablespoons butter
• 1/2 onion, thinly sliced
• 1 small zucchini, sliced into rounds (1/8 to 1/4 inch thick)
• 1 small yellow squash, sliced into rounds (1/8 to 1/4 inch thick)
• 2 large cloves garlic, minced
• 1/2 cup heavy cream
• 1/4 cup grated Parmesan cheese
• 1 cup shredded smoked Gouda cheese

Swaps and Notes

• Zucchini and Yellow Squash: The key here is even slicing for uniform cooking. If you don’t have both, you can use two of one kind. Other tender vegetables like thinly sliced eggplant or even blanched broccoli florets could work, but adjust cooking times as needed.
• Onion: A red onion can add a touch of color and slightly sharper flavor if you prefer.
• Garlic: Feel free to add an extra clove or two if you’re a garlic lover like me!
• Heavy Cream: There’s no real substitute for heavy cream in this recipe to get that rich, creamy texture. Half-and-half won’t be as thick.
• Parmesan Cheese: Freshly grated Parmesan cheese is always best for flavor and meltability.
• Smoked Gouda Cheese: This is a star ingredient for its unique smoky, nutty flavor. If you can’t find it, regular Gouda is fine, or you could try a sharp white cheddar or Gruyere for a similar melting quality and depth.
• Adding Herbs: A sprinkle of fresh thyme or rosemary added with the garlic would be a lovely aromatic addition.

---

Instructions

1. Preheat Oven: Preheat your oven to 450°F (230°C). If your skillet isn’t oven-safe, you’ll need to transfer the mixture to a gratin dish or small baking dish before baking.
2. Sauté Vegetables: In an oven-proof skillet (a 10-inch cast iron skillet works wonderfully), melt the 2 tablespoons of butter over medium heat.
3. Add the thinly sliced onion to the skillet and cook, stirring occasionally, until the edges begin to brown and the onion softens, about 5 minutes.
4. Stir in the 2 large cloves of minced garlic and cook for an additional minute, stirring frequently to ensure the garlic doesn’t burn.
5. Make the Cream Sauce: Pour the 1/2 cup heavy cream into the skillet with the onions and garlic. Bring the mixture to a gentle simmer, cooking until the cream starts to thicken and becomes bubbly, about 2-3 minutes.
6. Slowly stir in the 1/4 cup of grated Parmesan cheese until it’s fully incorporated into the creamy sauce.
7. Combine & Soften: Add the sliced zucchini and yellow squash rounds to the skillet. Gently stir to coat all the vegetables evenly in the creamy sauce.
8. Continue to cook for another 5 minutes, stirring occasionally, until the vegetables begin to soften slightly. They should still have a bit of bite, as they’ll continue to cook in the oven.
9. Add Gouda & Bake: Evenly sprinkle the 1 cup of shredded smoked Gouda cheese over the top of the vegetables in the skillet.
10. Carefully transfer the skillet to the preheated oven. Bake for 20 minutes, or until the cheese is beautifully melted, bubbly, and golden brown on top.
11. Rest & Serve: Remove the gratin from the oven and let it cool for a few minutes before serving. This allows the sauce to set slightly.

Enjoy this rich and creamy gratin as a delicious side dish or a light main course!

---

Tips for Success

• Even Slices are Key: Uniformly sliced zucchini and squash (1/8 to 1/4 inch thick) ensure they cook evenly. If slices are too thick, they won’t tenderize properly; if too thin, they might become mushy.
• Don’t Overcook the Vegetables on the Stovetop: The goal is just to start softening them before baking. They’ll finish cooking in the oven, staying tender-crisp rather than mushy.
• Hot Oven for Browning: The high oven temperature (450°F) is crucial for getting that beautiful golden, bubbly, and slightly crispy cheese topping.
• Smoked Gouda Makes a Difference: While other cheeses work, the smoked Gouda truly elevates the flavor profile of this gratin.
• Rest Before Serving: A short rest out of the oven allows the sauce to settle and thicken slightly, making it easier to serve.

Serving Suggestions and Pairings

This Creamy Zucchini and Squash Gratin is incredibly versatile. It makes a magnificent side dish to roasted chicken, baked fish, or grilled steak. It’s also hearty enough to be a light vegetarian main course, perhaps with a simple green salad on the side. For other comforting vegetable-forward dishes, you might enjoy my This Tomato Skillet With Okra And Sausage Is My Favorite Quick Dinner Packed With Southern Flavor (minus the sausage for a veggie version) or for another impressive appetizer, try This Baked Brie Appetizer Is My Favorite Effortless Way To Impress Guests.

Storage and Leftover Tips

Leftover Zucchini and Squash Gratin can be stored in an airtight container in the refrigerator for up to 2-3 days. To reheat, gently warm portions in the microwave or, for best results, in a preheated oven at 350°F (175°C) until heated through and bubbly again. The texture of the squash might be slightly softer upon reheating, but the flavor will still be delicious.

---

More Recipes You Will Love

If you appreciate the comforting and cheesy goodness of this gratin, you’ll want to explore these other Chefmaniac favorites:

• For another fantastic, easy casserole, check out This Dorito Casserole Is My Favorite Weeknight Dinner Shortcut.
• If you’re a fan of hearty, comforting stews with deep flavors, my This Cajun Chicken Sausage Gumbo Is My Favorite Bowl Of Southern Comfort is a must-try.
• And for a pasta dish that comes together quicker than you’d think while still delivering on comfort, dive into This Instant Pot Lasagna Is My Favorite Way To Make Comfort Food Fast.

Final Thoughts

This Creamy Zucchini and Squash Gratin is a delightful way to enjoy summer’s bounty, transforming humble vegetables into a rich, cheesy, and utterly satisfying dish. It’s perfect for adding a touch of elegance to your dinner table without hours of effort. Give it a try, and get ready for rave reviews!

What are your favorite ways to use summer zucchini and squash? Share your ideas in the comments below, and don’t forget to follow Chefmaniac.com for more delicious recipes!