Description
Zucchini and Yellow Squash Au Gratin combines fresh zucchini and yellow squash slices, layered with a rich cream sauce made from sautéed onions, garlic, and a blend of Parmesan and Gruyère cheeses. Baked until golden with a crispy breadcrumb topping, the dish is finished with a sprinkle of fresh parsley. It’s a comforting casserole perfect for showcasing summer squash in a creamy, cheesy format.
Ingredients
- 2 medium zucchinis, thinly sliced
- 2 medium yellow squashes, thinly sliced
- 1 tbsp olive oil
- 1/2 cup diced onion
- 2 cloves garlic, minced
- 1 cup heavy cream
- 1/2 cup grated Parmesan cheese
- 1 cup shredded Gruyère or Swiss cheese, divided
- 1/2 tsp dried thyme
- Salt and pepper, to taste
- 1/4 cup bread crumbs (optional, for a crispy topping)
- Fresh parsley, chopped (for garnish)
Instructions
- Preheat your oven to 400°F (200°C) and grease an 8×8-inch baking dish.
- Heat olive oil in a skillet over medium heat. Sauté diced onion for 3–4 minutes until translucent.
- Add minced garlic to the skillet and cook for 1–2 minutes until fragrant.
- Stir in heavy cream, 1/4 cup Parmesan cheese, 1/2 cup Gruyère cheese, dried thyme, salt, and pepper. Mix until cheese melts and sauce is creamy. Remove from heat.
- Layer half of the zucchini and yellow squash slices in the prepared baking dish, overlapping slightly.
- Pour half of the cream mixture over the squash, spreading evenly. Repeat with the remaining squash and cream mixture.
- Sprinkle the remaining 1/4 cup Parmesan cheese and 1/2 cup Gruyère cheese on top. If desired, add bread crumbs for a crispy topping.
- Cover with foil and bake for 20 minutes.
- Remove foil and continue baking for 15–20 minutes until the top is golden brown and squash is tender.
- Let cool for a few minutes, then garnish with chopped fresh parsley before serving.
Notes
For a lighter version, substitute half-and-half for heavy cream and use low-fat cheese. Swiss cheese can replace Gruyère, and gluten-free breadcrumbs make it celiac-friendly. Assemble the dish a day ahead, refrigerate, then bake when ready. Store leftovers in an airtight container in the fridge for up to 3 days; reheat in the oven to maintain crispiness. If sauce is too loose, bake uncovered a bit longer until it thickens.
- Prep Time: 15 minutes
- Cook Time: 40 minutes
- Category: Side Dish
- Method: Baking
- Cuisine: French
Nutrition
- Serving Size: 1/6th of the casserole
- Calories: 250
- Sugar: 4g
- Sodium: 340mg
- Fat: 19g
- Saturated Fat: 11g
- Unsaturated Fat: 8g
- Trans Fat: 0g
- Carbohydrates: 11g
- Fiber: 2g
- Protein: 9g