Indulge in the creamy, golden goodness of Summer Squash Au Gratin—a comforting yet elegant casserole dish that celebrates the vibrant flavors of seasonal produce. This recipe layers tender rounds of yellow squash and zucchini with a luscious garlic-infused cheese sauce made from Gruyere and Parmesan, creating a rich and velvety base. Topped with crispy panko breadcrumbs mixed with even more cheese and fresh thyme, the gratin is baked to bubbly perfection in just 35 minutes. Perfect for summer gatherings or a cozy side dish, this recipe is a delectable way to highlight fresh squash while satisfying your cravings for cheesy, indulgent comfort food.
Preheat your oven to 375°F (190°C). Grease a 9x13-inch baking dish with a bit of butter or olive oil and set aside.
Wash and trim the ends of the yellow squash and zucchini. Using a sharp knife or mandoline, slice them into 1/4-inch thick rounds.
Place the sliced squash in a large mixing bowl, sprinkle with 1/2 teaspoon of salt, and toss to coat. Let sit for 10 minutes to draw out excess moisture. Afterward, pat the squash dry with a kitchen towel or paper towels.
In a medium saucepan, melt the butter over medium heat. Add the minced garlic and cook for about 1 minute until fragrant.
Whisk in the flour to form a roux, cooking for another minute to eliminate the raw flour taste. Gradually whisk in the milk and cream, stirring constantly to prevent lumps.
Continue cooking until the sauce thickens slightly (about 3–4 minutes). Remove from heat and stir in 3/4 cup of gruyere cheese, 1/4 cup of parmesan cheese, 1/2 teaspoon of salt, black pepper, and fresh thyme.
Arrange half of the squash slices in an even layer in the prepared baking dish. Pour half of the cheese sauce over the squash, spreading evenly. Repeat with the remaining squash and cheese sauce.
In a small bowl, toss the panko breadcrumbs with olive oil and the remaining gruyere and parmesan cheese. Sprinkle this mixture evenly over the top of the dish.
Bake in the preheated oven for 25–30 minutes, or until the top is golden brown and bubbly.
Remove from the oven and let the gratin cool for 5 minutes before serving. Garnish with a little extra thyme if desired.
Calories |
1538 | ||
|---|---|---|---|
% Daily Value* |
|||
| Total Fat | 119.3 g | 153% | |
| Saturated Fat | 63.5 g | 318% | |
| Polyunsaturated Fat | 1.6 g | ||
| Cholesterol | 317 mg | 106% | |
| Sodium | 4352 mg | 189% | |
| Total Carbohydrate | 62.5 g | 23% | |
| Dietary Fiber | 4.6 g | 16% | |
| Total Sugars | 29.1 g | ||
| Protein | 46.6 g | 93% | |
| Vitamin D | 0.0 mcg | 0% | |
| Calcium | 1337 mg | 103% | |
| Iron | 3.2 mg | 18% | |
| Potassium | 899 mg | 19% | |
*The % Daily Value tells you how much a nutrient in a serving of food contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.