Zucchini Gratin with Yellow Squash

There’s something magical about turning a handful of simple vegetables into a dish that disappears before dinner is even over. That’s exactly what happens with Zucchini Gratin with Yellow Squash. Tender summer squash, sweet onions, rich cream, and a blanket of golden melted cheese come together in one skillet to create a side dish that feels both comforting and a little fancy.

If your garden is overflowing with zucchini or you’ve spotted beautiful yellow squash at the market, this recipe is the perfect answer. It’s easy enough for a busy weeknight yet impressive enough to earn compliments at family gatherings, potlucks, and holiday dinners. Best of all, your kitchen will smell like a cozy bistro while it bakes.

As Chef Omar always says, great cooking doesn’t have to be complicated. Sometimes a few fresh ingredients and plenty of cheese are all you need to make something unforgettable.

Why You’ll Love This Zucchini Gratin with Yellow Squash

This dish checks all the boxes for home cooks looking for a dependable vegetable side dish:

• Ready in about 45 minutes from start to finish.
• Uses simple ingredients you can find anywhere.
• Rich, creamy, and packed with flavor.
• A fantastic way to enjoy summer squash.
• Family-friendly, even for people who usually avoid vegetables.
• Easy to customize with different cheeses and seasonings.

One of my favorite things about this recipe is how often it surprises people. I’ve served it at gatherings where guests claimed they weren’t zucchini fans, only to come back for seconds—and sometimes thirds.

Ingredients You’ll Need

For this Zucchini Gratin with Yellow Squash, gather the following 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 garlic cloves, minced
• 1/2 cup heavy cream
• 1/4 cup grated Parmesan cheese
• 1 cup shredded smoked Gouda cheese

Ingredient Notes

Zucchini and Yellow Squash
Smaller squash tend to be more tender and cook more evenly. If you’re using larger late-season squash, you may need additional cream and a little extra cooking time.

Smoked Gouda
This cheese adds incredible depth and a subtle smoky flavor. Many home cooks have successfully substituted sharp cheddar, mozzarella, Asiago, or pepper jack when needed.

Parmesan
Freshly grated Parmesan provides excellent flavor, while pre-grated Parmesan can sometimes help create a slightly thicker sauce.

How to Make Zucchini Gratin with Yellow Squash

Step 1: Prepare the Oven

Preheat your oven to 450°F.

A hot oven is key to achieving that gorgeous golden-brown cheesy topping everyone fights over.

Step 2: Cook the Onion

Place an oven-safe skillet over medium heat and melt the butter.

Add the sliced onion and cook for about 5 minutes until the edges begin to brown and caramelize slightly.

Step 3: Add the Garlic

Stir in the minced garlic and cook for about 1 minute.

You’ll know it’s ready when your kitchen starts smelling absolutely amazing.

Step 4: Create the Cream Sauce

Pour in the heavy cream and bring it to a gentle simmer.

Allow the cream to bubble for a few minutes until it starts thickening slightly. Slowly stir in the Parmesan cheese until smooth and creamy.

Step 5: Add the Squash

Add the sliced zucchini and yellow squash to the skillet.

Cook for 4 to 5 minutes, stirring occasionally so the vegetables become lightly tender and coated in the creamy sauce.

Step 6: Top with Cheese

Sprinkle the shredded smoked Gouda evenly over the top.

Don’t be shy here. The cheesy crust is one of the best parts of this zucchini gratin recipe.

Step 7: Bake Until Golden

Transfer the skillet to the oven.

Bake for 15 to 20 minutes, or until the cheese is bubbly, melted, and beautifully golden brown.

Allow the dish to rest for a few minutes before serving.

Chef Omar’s Tips for Success

Let the Cream Thicken First

Several home cooks found that allowing the cream to reduce a bit longer before adding the squash created a thicker, creamier final dish.

Adjust for Larger Squash

Large zucchini and yellow squash naturally release more moisture. If using oversized vegetables, consider doubling the cream and Parmesan as needed.

Add a Little Seasoning

While the original recipe keeps things simple, a pinch of salt and freshly cracked black pepper can elevate the flavors beautifully.

Italian seasoning, oregano, or rosemary also pair wonderfully with this dish.

Slice Carefully

For the best texture, aim for slices between 1/8 and 1/4 inch thick. Too thin and the squash can become overly soft. Too thick and it may require extra baking time.

And if a few slices end up uneven, don’t worry. Vegetables have personalities too.

Delicious Variations

One reason this Zucchini Gratin with Yellow Squash has become such a favorite is its flexibility.

Extra Cheesy Version

Mix smoked Gouda with:

• Mozzarella
• Sharp cheddar
• Asiago
• Monterey Jack

The combination creates an even richer flavor profile.

Add Bacon

A few crumbles of crispy bacon add a smoky, savory twist that’s hard to resist.

Include Tomatoes

Sliced ripe tomatoes add beautiful color and a fresh burst of flavor that complements the creamy sauce.

Make It Heartier

Add cooked chicken sausage, sweet corn, or extra vegetables to transform this side dish into a satisfying meal.

A Family Favorite for Any Occasion

I first started making gratins like this when friends would stop by unexpectedly around dinner time. The beauty of a recipe like this is that it feels special without requiring hours in the kitchen.

Over the years, I’ve watched countless guests scrape the skillet clean. In fact, one of the most common comments about this dish is that there are never any leftovers. That’s usually the highest compliment a recipe can receive.

Whether you’re serving grilled chicken, steak, pork chops, or a holiday roast, this cheesy vegetable side fits right in.

Frequently Asked Questions

A Cheesy Side Dish Worth Making Again

When you need a vegetable side dish that feels comforting, elegant, and surprisingly easy, Zucchini Gratin with Yellow Squash delivers every time. The combination of tender squash, creamy Parmesan sauce, sweet onions, and golden melted Gouda creates a dish that’s rich without being complicated.

Whether you’re looking for a new way to use garden zucchini or simply want a side dish that earns rave reviews, this recipe belongs in your regular rotation. Grab your skillet, gather your ingredients, and let this Zucchini Gratin with Yellow Squash bring a little extra warmth and cheesy goodness to your table. Happy cooking!

More Fresh and Flavorful Ways to Enjoy Summer Vegetables

If this Zucchini Gratin with Yellow Squash earned a spot on your dinner table, there are plenty of other delicious ways to make the most of seasonal produce. From colorful vegetable-packed dishes to light and refreshing sides, these recipes pair beautifully with everything from grilled chicken to hearty family dinners:

• Enjoy another garden-inspired favorite with this Easy Ratatouille Recipe, featuring a delicious blend of zucchini, tomatoes, and herbs.
• Add even more color to your plate with these Garlic Roasted Vegetables, a simple side dish packed with savory flavor.
• If cheesy vegetable recipes are your thing, these Broccoli Cheese Patties offer crispy edges and plenty of comforting goodness.
• Balance the richness of this gratin with a bright and refreshing Easy Lemon Parmesan Lettuce Salad that’s perfect for warm-weather meals.
• For another classic take on this comforting dish, explore this Zucchini and Squash Au Gratin Recipe, a longtime favorite that celebrates the simple combination of tender squash and melted cheese.

Zucchini Gratin with Yellow Squash

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• Author: Omar
• Total Time: 45 minutes
• Yield: 4 servings 1x
• Diet: Vegetarian

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Description

This Zucchini Gratin with Yellow Squash is a rich and creamy side dish featuring tender summer squash, sweet onions, Parmesan cheese, and smoked Gouda baked until golden and bubbly. Easy enough for weeknights and elegant enough for holiday dinners, it’s a delicious way to enjoy fresh seasonal vegetables.

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Ingredients

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• 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 garlic cloves, minced
• 1/2 cup heavy cream
• 1/4 cup grated Parmesan cheese
• 1 cup shredded smoked Gouda cheese

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Instructions

1. Preheat oven to 450°F (230°C).
2. Melt butter in an oven-safe skillet over medium heat.
3. Add the sliced onion and cook until lightly browned, about 5 minutes.
4. Stir in the garlic and cook for 1 minute.
5. Pour in the heavy cream and simmer until bubbly and slightly thickened.
6. Gradually stir in the Parmesan cheese until incorporated.
7. Add the zucchini and yellow squash slices and cook for 4–5 minutes.
8. Sprinkle the smoked Gouda evenly over the top.
9. Transfer the skillet to the oven and bake for 15–20 minutes, or until the cheese is golden brown and bubbly.
10. Let rest for a few minutes before serving.

Notes

If using large late-season zucchini or squash, double the cream and Parmesan cheese for the best texture.

Larger squash may require additional simmering and baking time.

Season with salt and black pepper to taste if desired.

Sharp cheddar, mozzarella, or Asiago can be substituted for the smoked Gouda.

For a thicker sauce, allow the cream to reduce slightly longer before adding the squash.

• Prep Time: 10 minutes
• Cook Time: 35 minutes
• Category: Side Dish
• Method: Baking
• Cuisine: American

Nutrition

• Serving Size: 1 serving
• Calories: 412
• Sugar: 5g
• Sodium: 653mg
• Fat: 35g
• Saturated Fat: 22g
• Unsaturated Fat: 10g
• Trans Fat: 0.2g
• Carbohydrates: 8g
• Fiber: 1g
• Protein: 19g
• Cholesterol: 122mg