This Zucchini and Yellow Squash Au Gratin is a delicious, creamy, and cheesy side dish that turns simple summer squash into something truly special. With a crispy golden top and tender slices of zucchini and yellow squash beneath, it’s a lighter twist on the traditional potato gratin but still packed with flavor.
Why I Love This Recipe
I love how this dish highlights the natural sweetness and tenderness of summer squash while delivering that satisfying richness I usually get from a gratin. It's a great way to use up extra zucchini and yellow squash during the peak season. Plus, it pairs beautifully with grilled meats, roasts, or as a standalone vegetarian option.
ingredients
(Here's a tip: Check out the full list of ingredients and measurements in the recipe card below.)
- Zucchini
- Yellow squash
- Garlic
- Shallot
- Whole milk
- All-purpose flour
- Freshly grated Parmesan cheese
- Sharp white cheddar cheese
- Olive oil
- Salt
- Black pepper
- Fresh thyme (optional, for garnish)
directions
- I start by slicing the zucchini and yellow squash thinly and evenly for uniform cooking.
- Then I sauté garlic and shallot in olive oil until fragrant.
- I sprinkle in the flour to create a roux, then slowly whisk in the milk to form a creamy base.
- I remove the pan from heat and stir in a portion of the cheeses until melted.
- In a greased baking dish, I layer the zucchini and squash, then pour the cheese sauce evenly over the top.
- I finish it off with the remaining cheeses sprinkled over the surface.
- The dish goes into a preheated oven at 400°F (200°C) for about 25–30 minutes, until bubbly and golden brown.
- For an extra golden crust, I broil it briefly at the end.
Servings and timing
This recipe makes about 6 servings. The prep takes roughly 15 minutes, and the cooking time is around 30 minutes, with an optional 2–3 minutes under the broiler.
Variations
I sometimes add breadcrumbs on top before baking for an extra crunch. Mixing in other cheeses like Gruyère or mozzarella gives it a different flavor profile. For a heartier version, I’ve also layered in some cooked quinoa or even thin slices of cooked potato.
storage/reheating
I store leftovers in an airtight container in the refrigerator for up to 3 days. To reheat, I use the oven at 350°F (175°C) until warmed through, or I microwave it in short intervals, though the oven keeps the top nice and crispy.
FAQs
How do I keep the squash from getting watery?
I usually salt the slices and let them sit for 10 minutes, then pat them dry to reduce moisture.
Can I use just zucchini or just yellow squash?
Yes, I’ve used only zucchini or only yellow squash when that’s what I had on hand. It works just as well.
Can I make this recipe ahead of time?
I often prepare it up to the baking step, cover it, and refrigerate it. Then I bake it just before serving.
What’s the best cheese to use?
I like sharp cheddar for bold flavor and Parmesan for a salty kick. Gruyère also works beautifully if I want something fancier.
Can I make this dish gluten-free?
Yes, I use a gluten-free flour blend in the roux or substitute with cornstarch for thickening.
Conclusion
Zucchini and Yellow Squash Au Gratin is one of my go-to comfort dishes that still feels light and fresh. It's creamy, cheesy, and full of garden flavor. Whether I’m making it for a weeknight dinner or a special gathering, it’s always a hit.
Zucchini and Yellow Squash Au Gratin
- Prep Time: 15 minutes
- Cook Time: 30 minutes
- Total Time: 45 minutes
- Yield: 6 servings
- Category: Side Dish
- Method: Baking
- Cuisine: American
- Diet: Vegetarian
Description
Zucchini and Yellow Squash Au Gratin is a creamy, cheesy, and irresistible summer side dish made with tender squash, garlic, and a rich homemade cheese sauce. This lighter twist on classic gratin is perfect for showcasing fresh garden vegetables and pairs beautifully with any main course.
Ingredients
- Zucchini
- Yellow squash
- Garlic
- Shallot
- Olive oil
- All-purpose flour (or gluten-free blend)
- Whole milk
- Freshly grated Parmesan cheese
- Sharp white cheddar cheese
- Salt
- Black pepper
- Fresh thyme (optional, for garnish)
Instructions
- Preheat oven to 400°F (200°C).
- Thinly slice zucchini and yellow squash.
- Sauté garlic and shallot in olive oil until fragrant.
- Stir in flour to create a roux, then whisk in milk gradually until smooth.
- Remove from heat and stir in half the cheeses until melted.
- In a greased baking dish, layer zucchini and squash.
- Pour cheese sauce evenly over the layers.
- Sprinkle remaining cheese on top.
- Bake for 25–30 minutes, until bubbly and golden.
- Optional: Broil for 2–3 minutes for a crispier top.
- Garnish with fresh thyme if desired.
Notes
- For less watery squash, salt slices and let sit for 10 minutes before patting dry.
- Add breadcrumbs for extra crunch.
- Try Gruyère or mozzarella for a different cheesy twist.
- Can be made ahead up to baking step.
- Gluten-free option: Use a GF flour blend or cornstarch.
- Stores well in the fridge for up to 3 days.
