If you’re searching for a vibrant, cheesy, and irresistibly creamy side that steals the spotlight, look no further than Zucchini and Yellow Squash Au Gratin. This French-inspired classic weaves fresh, summer squash with a luscious cheese sauce and a golden panko crust for a dish that’s equal parts comfort and sophistication. Whether you’re serving weeknight dinner or entertaining guests, Zucchini and Yellow Squash Au Gratin is a flavorful way to make your veggies feel special.
Ingredients You’ll Need
This recipe keeps things simple with fresh produce, kitchen staples, and a few decadent ingredients. Each one plays a role in building layers of flavor, creaminess, and that golden top everyone fights for at the table.
- Zucchini: Thinly sliced, it brings tenderness and a mild, earthy flavor that soaks up the cheese sauce beautifully.
- Yellow squash: Just as tender as zucchini but with a subtly sweet, buttery taste that adds color and variety.
- Olive oil: Used to sauté the veggies and aromatics, imparting a lovely, rich undertone.
- Onion: Sliced thin, it melts into the gratin for a gentle, savory flavor base.
- Garlic: Just a touch for depth and aroma—don’t skip this step!
- Heavy cream: Creates a luxuriously creamy sauce that envelopes the vegetables.
- Parmesan cheese: Adds a salty kick and helps the sauce thicken to perfection.
- Gruyère or mozzarella cheese: Choose Gruyère for a nutty, classic flavor, or mozzarella for extra melt and mildness.
- Salt: Enhances all the flavors; taste as you go to get it just right.
- Black pepper: A pinch brings a little warmth and rounds out the dish.
- Dried thyme: Brings in a cozy, herby note that pairs perfectly with the cheese.
- Panko breadcrumbs: Ensures your crust turns out wonderfully crisp.
- Butter: Melted and mixed with panko for a golden, irresistible topping.
- Chopped fresh parsley (optional): Brightens everything up at the very end.
How to Make Zucchini and Yellow Squash Au Gratin
Step 1: Prep Your Ingredients
Preheat your oven to 375°F (190°C) and lightly grease a 9×13-inch baking dish. Thinly slice your zucchini, yellow squash, and onion—this step guarantees even baking and that tender, melt-in-your-mouth texture that makes Zucchini and Yellow Squash Au Gratin so memorable.
Step 2: Sauté the Vegetables
Heat the olive oil in a large skillet over medium heat. Toss in the onion and cook for 4–5 minutes, stirring occasionally until it turns translucent and soft. Add the garlic, letting it sizzle for a minute until fragrant, then fold in your zucchini and yellow squash. Give them about 5–7 minutes, just until they’re beginning to soften but still hold their color. Season with salt, black pepper, and thyme, then remove from the heat.
Step 3: Make the Creamy Cheese Sauce
In a separate saucepan over medium heat, gently warm the heavy cream. Whisk in your Parmesan and Gruyère (or mozzarella) gradually, stirring until you have a silky, cheesy sauce. The secret to great Zucchini and Yellow Squash Au Gratin is letting the cheeses melt completely for a velvety texture, so be patient and keep stirring!
Step 4: Assemble the Gratin
Pour the hot cheese sauce directly over your sautéed vegetables in the skillet and gently mix everything together, making sure every slice is coated in that glorious sauce. Transfer your mixture into the prepared baking dish, smoothing out the top for an even bake.
Step 5: Add the Crunchy Panko Topping
In a small bowl, combine the panko breadcrumbs with melted butter, stirring until every crumb glistens. Scatter this mixture evenly over your assembled gratin. This panko layer bakes into a gorgeous, golden crust that’s truly the signature of a proper Zucchini and Yellow Squash Au Gratin.
Step 6: Bake to Perfection
Slide your dish into the oven and bake for 20–25 minutes. It’s done when the sides are bubbling, the top is golden brown, and the kitchen smells like absolute heaven. Let the gratin cool for a few minutes before digging in—if you can wait!
How to Serve Zucchini and Yellow Squash Au Gratin
Garnishes
A sprinkle of chopped fresh parsley lends a pop of color and freshness to your Zucchini and Yellow Squash Au Gratin, balancing out the richness of the cheese and butter. Try a pinch of cracked black pepper or a dusting of extra Parmesan if you’re feeling fancy!
Side Dishes
This gratin is a showstopper beside roasted chicken, seared pork chops, or a simple grilled steak. For a full vegetarian spread, pair it with a leafy green salad and warm crusty bread—perfect for sopping up every last bit of sauce.
Creative Ways to Present
If you want to elevate the presentation, assemble the Zucchini and Yellow Squash Au Gratin in individual ramekins for dinner parties or holiday gatherings. The mini servings look charming and ensure everyone gets plenty of that crisp panko topping!
Make Ahead and Storage
Storing Leftovers
Leftover Zucchini and Yellow Squash Au Gratin can be kept in an airtight container in the refrigerator for up to 3 days. The flavors mellow and deepen, making your next-day lunch or dinner even more delicious.
Freezing
While this dish is at its very best fresh, you can freeze it for longer storage. Assemble the gratin (but don’t bake or add the panko topping yet), wrap it tightly, and freeze for up to 2 months. Thaw overnight in the fridge before topping with panko and baking as directed.
Reheating
To reheat, cover loosely with foil and warm in a 350°F (175°C) oven until heated through. If you want to restore the crunchy topping, remove the foil for the last 5 minutes. Microwave reheating works too, but the crust won’t be as crisp.
FAQs
Can I make Zucchini and Yellow Squash Au Gratin ahead of time?
Absolutely! You can assemble everything except the panko topping and keep it refrigerated for up to a day ahead. When you’re ready to bake, sprinkle the buttered panko on top and pop it in the oven fresh. This way, you get the convenience of prep ahead and the magic of a crisp, just-baked crust.
What cheese is best for this gratin?
Gruyère melts beautifully and brings a nutty depth that’s classic in French-inspired gratins, but mozzarella is a great substitute if you want something milder or more gooey. Don’t forget the Parmesan—it’s essential for a punch of salty flavor!
How can I make this recipe gluten-free?
Simply use gluten-free panko breadcrumbs or omit the breadcrumb topping altogether. The gratin stays creamy and cheesy, and you won’t miss the crunch too much—though gluten-free panko gets you very close to the original experience.
Can I swap the heavy cream for something lighter?
You can! Half-and-half works well, as does your favorite plant-based cream for a dairy-free version. Just know that lower-fat options may make the sauce a little thinner, but the dish will still be delicious.
Does this dish work as a main course?
It absolutely can! For a satisfying vegetarian meal, serve Zucchini and Yellow Squash Au Gratin alongside a hearty grain salad and some roasted vegetables. Or add chickpeas or white beans to the gratin for an extra boost of protein.
Final Thoughts
There’s something truly special about sharing a bubbling, cheesy pan of Zucchini and Yellow Squash Au Gratin with the people you love. I hope you give this recipe a place at your table—it’s vibrant, comforting, and just a little bit luxurious. Happy cooking!
Print
Zucchini and Yellow Squash Au Gratin Recipe
- Total Time: 40 minutes
- Yield: 6 servings 1x
- Diet: Vegetarian
Description
Indulge in this creamy and cheesy Zucchini and Yellow Squash Au Gratin that makes the perfect side dish for any occasion. Layers of tender zucchini and yellow squash are bathed in a luscious cheese sauce, topped with crispy breadcrumbs, and baked until golden brown.
Ingredients
Zucchini and Yellow Squash:
- 2 medium zucchinis, thinly sliced
- 2 medium yellow squash, thinly sliced
Cheese Sauce:
- 2 tablespoons olive oil
- 1 small onion, thinly sliced
- 2 garlic cloves, minced
- 1 cup heavy cream
- ½ cup grated Parmesan cheese
- 1 cup shredded Gruyère or mozzarella cheese
- ½ teaspoon salt
- ¼ teaspoon black pepper
- ¼ teaspoon dried thyme
Topping:
- ½ cup panko breadcrumbs
- 1 tablespoon butter, melted
- Chopped fresh parsley for garnish, optional
Instructions
- Preheat the oven: Preheat oven to 375°F (190°C) and grease a 9×13-inch baking dish.
- Sauté vegetables: In a skillet, cook onion in olive oil until softened. Add garlic, zucchini, and squash. Sauté until tender, season with salt, pepper, and thyme.
- Make cheese sauce: Heat cream, add Parmesan and Gruyère until smooth. Pour over vegetables in baking dish.
- Add topping: Combine panko with butter, sprinkle over gratin.
- Bake: Bake for 20–25 minutes until golden. Let cool slightly, garnish with parsley, and serve.
Notes
- To make gluten-free, use gluten-free panko or omit topping.
- Substitute cream with half-and-half or plant-based alternative if desired.
- Prep Time: 15 minutes
- Cook Time: 25 minutes
- Category: Side Dish
- Method: Baking
- Cuisine: French-Inspired
Nutrition
- Serving Size: 1 cup
- Calories: 270
- Sugar: 4g
- Sodium: 320mg
- Fat: 20g
- Saturated Fat: 11g
- Unsaturated Fat: 8g
- Trans Fat: 0g
- Carbohydrates: 13g
- Fiber: 2g
- Protein: 8g
- Cholesterol: 50mg
