Zucchini and Yellow Squash Au Gratin
This Zucchini and Yellow Squash Au Gratin is a creamy cheesy baked dish that transforms simple summer squash into a luxurious side. With tender layers of zucchini and yellow squash smothered in a garlicky cream sauce and topped with golden melted cheese, it’s the perfect comforting addition to any dinner. Whether you’re cooking for a weeknight meal or a special gathering, this dish brings a touch of elegance with minimal effort.
Prep Time: 15 minutes
Cook Time: 25–30 minutes
Total Time: 40–45 minutes
Servings: 4–6
Ingredients
2 medium zucchinis thinly sliced
2 medium yellow squash thinly sliced
2 tablespoons butter
2 garlic cloves minced
2 tablespoons all-purpose flour
1 cup milk or half-and-half
1/2 cup grated parmesan cheese
1/2 cup shredded mozzarella or gruyère
Salt and pepper to taste
1/4 teaspoon dried thyme or Italian seasoning (optional)
1/4 cup breadcrumbs (optional for topping)
Instructions
Preheat Oven
Preheat your oven to 375°F (190°C). Lightly grease a baking dish.
Prepare the Sauce
In a saucepan melt butter over medium heat. Add garlic and cook for 30 seconds. Whisk in flour and cook for 1 minute until slightly golden. Slowly whisk in milk and stir until thickened, 3–5 minutes. Add salt, pepper, and seasoning. Stir in parmesan and remove from heat.
Assemble the Dish
Layer the sliced zucchini and squash in the baking dish, alternating for color. Pour the cream sauce evenly over the vegetables.
Top with Cheese
Sprinkle mozzarella (or gruyère) over the top. Add breadcrumbs if using for extra crunch.
Bake
Bake uncovered for 25–30 minutes until bubbly and golden on top. Broil for the last 2 minutes for a crispier top if desired.
Serve
Let cool slightly before serving. Garnish with fresh herbs if desired.
Tips
Slice Evenly
Use a mandoline or sharp knife to slice the zucchini and squash evenly for uniform cooking.
Remove Excess Moisture
Lightly salt the squash slices and let them sit for 10 minutes then pat dry. This prevents a watery gratin.
Make Ahead
You can prep and assemble the dish a few hours ahead and bake just before serving.
Broil for Texture
Broiling the top for 1–2 minutes adds a beautiful golden crust.
Variations
Add Protein
Mix in cooked chicken sausage or crumbled bacon for a heartier dish.
Go Low-Carb
Skip the flour and thicken the sauce with cream cheese or reduce cream longer.
Swap Cheeses
Try sharp cheddar fontina or Swiss for different flavor profiles.
Add Tomatoes
Layer in a few tomato slices for color and extra flavor.
Herb It Up
Fresh basil thyme or oregano can enhance the dish with bright herbal notes.
Quick Q&A
Can I use only zucchini or only yellow squash?
Yes you can use just one type of squash if preferred though using both adds color and flavor contrast
Can I make it dairy-free?
Yes use plant-based butter milk and cheese alternatives but be sure to use ones that melt well
Will it freeze well?
It’s best enjoyed fresh but you can freeze leftovers. Reheat in the oven for best texture
Can I add breadcrumbs to the top?
Yes adding breadcrumbs gives a nice crunch. Toast them lightly before baking for extra crispness
Nutrition (Approx. per serving — based on 6 servings)
Calories: 180–220
Protein: 7–9g
Fat: 12–15g
Carbs: 10–14g
Fiber: 2g
Sodium: 300–400mg
Conclusion
Zucchini and Yellow Squash Au Gratin is a simple yet elegant way to enjoy fresh summer vegetables in a rich comforting form. With layers of tender squash creamy garlic sauce and golden melted cheese it’s a side dish that feels indulgent but is full of wholesome ingredients. Perfect for family dinners potlucks or holidays it’s a versatile recipe you’ll return to again and again.