Cheesy Squash and Zucchini Casserole

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This Cheesy Squash and Zucchini Casserole is the kind of dish that brings warmth to any table. Golden, bubbly cheese crowns a bed of tender summer squash and zucchini slices, all nestled in a creamy, savory blend that feels both indulgent and comforting. The natural sweetness of the squash and zucchini contrasts beautifully with the sharpness of the cheese and richness of the cream, creating layers of flavor in every bite.

Perfect as a weeknight side or a holiday centerpiece, this casserole is a beautiful way to celebrate seasonal produce. It’s hearty without being heavy, and versatile enough to pair with grilled meats, roasted chicken, or even served solo as a light vegetarian dinner. Plus, it’s one of those dishes that’s just as good reheated the next day — if you’re lucky enough to have leftovers.

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Why You’ll Love This Cheesy Squash and Zucchini Casserole

• Comforting and cozy: Think cheesy, golden-topped casserole that’s satisfying yet vegetable-forward.
• Great way to use summer produce: Especially perfect when zucchini and squash are overflowing in the garden or market.
• Crowd-pleaser: Even veggie skeptics will devour this thanks to its rich, creamy, cheesy flavor.
• Make-ahead friendly: Assemble in advance and bake when ready — great for holidays or busy weeknights.
• Versatile: Serve as a side dish or main, and it’s easily adaptable to include protein or other veggies.

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Preparation Phase & Tools to Use (Essential Tools and Equipment, Plus the Importance of Each Tool)

Getting this Cheesy Squash and Zucchini Casserole just right starts with having the right tools. While it’s a straightforward dish, using quality tools helps ensure even baking, perfect texture, and a fuss-free cooking experience.

• Mandoline or sharp chef’s knife: Essential for slicing zucchini and squash into thin, even rounds. Uniform slices ensure even cooking and a professional appearance.
• Large skillet or sauté pan: Used for pre-cooking the vegetables slightly to reduce moisture. This step keeps your casserole from turning watery.
• Mixing bowls: You’ll need at least one large bowl to combine the creamy filling and cheeses evenly.
• Colander: For draining excess moisture from the salted squash and zucchini — a critical step in keeping the texture just right.
• 9×13-inch baking dish: The ideal size for layering your ingredients and achieving that perfect bubbly, golden top.
• Box grater or pre-shredded cheese: Grate your own cheese for optimal melt and flavor or use pre-shredded in a pinch.
• Aluminum foil: To cover during the first part of baking so the cheese doesn’t brown too quickly.
• Oven mitts: Safety first — this dish comes out hot and bubbly.

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Preparation Tips

• Salt the veggies and let them rest: Toss the sliced zucchini and squash with salt and let them sit for about 20–30 minutes. This draws out excess water, preventing a soggy casserole.
• Pat dry thoroughly: After draining, gently press the slices with a paper towel to remove even more moisture.
• Don’t skip the sauté step: Lightly cooking the squash before assembling helps enhance flavor and ensures they’re perfectly tender.
• Use full-fat dairy: Cream and cheese bring richness and stability. Skimping may alter the texture and taste.
• Shred cheese fresh: Pre-shredded cheese contains anti-caking agents, which can affect how it melts. Freshly shredded gives the best result.
• Let it rest after baking: Give the casserole 5–10 minutes to set before serving so the creamy filling holds together better when sliced.

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Ingredients for This Cheesy Squash and Zucchini Casserole

To make this comforting and flavor-packed casserole, you’ll need a mix of fresh produce, dairy, and a few pantry staples. Here’s everything you need:

• 2 medium zucchini, thinly sliced
• 2 medium yellow squash, thinly sliced
• 1 tablespoon salt (for draining moisture from vegetables)
• 1 tablespoon olive oil
• 1 small onion, finely diced
• 2 cloves garlic, minced
• 1 cup sour cream
• 1/2 cup mayonnaise
• 1 large egg, beaten
• 1 1/2 cups shredded sharp cheddar cheese
• 1/2 cup grated Parmesan cheese
• 1/2 teaspoon black pepper
• 1/2 teaspoon dried thyme
• 1/2 teaspoon garlic powder
• 1/4 cup chopped fresh parsley (plus extra for garnish)
• 1 cup shredded mozzarella cheese (for topping)
• Butter or cooking spray (for greasing the baking dish)

These ingredients combine to create a casserole that’s creamy, cheesy, and perfectly balanced in flavor and texture — making it a must-have for dinner or special occasions.

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Step 1: Prep the Vegetables

Start by thinly slicing the zucchini and yellow squash into even rounds, about 1/8-inch thick. Place them in a large colander, sprinkle with 1 tablespoon of salt, and toss to coat. Let them sit for 20–30 minutes to draw out excess moisture. Afterward, gently press the slices with paper towels to remove as much liquid as possible.

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Step 2: Sauté the Aromatics and Squash

In a large skillet over medium heat, add 1 tablespoon of olive oil. Sauté the diced onion for 3–4 minutes until softened, then add the garlic and cook for another 30 seconds. Add the drained squash and zucchini slices and cook for 5–7 minutes, stirring occasionally, until slightly tender but not mushy. Remove from heat and let cool slightly.

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Step 3: Make the Creamy Mixture

In a large mixing bowl, whisk together the sour cream, mayonnaise, beaten egg, black pepper, thyme, and garlic powder. Stir in the shredded cheddar, Parmesan, and chopped parsley until well combined.

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Step 4: Combine and Layer

Preheat the oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish with butter or cooking spray. Add the cooked squash mixture to the bowl with the creamy cheese mixture and gently fold everything together until fully coated. Spread evenly in the prepared dish.

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Step 5: Add the Topping and Bake

Sprinkle the shredded mozzarella cheese evenly over the top. Cover the dish with foil and bake for 20 minutes. Then, remove the foil and bake uncovered for another 15–20 minutes, or until the top is golden brown and bubbly.

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Step 6: Let It Rest and Serve

Remove the casserole from the oven and let it rest for about 5–10 minutes before serving. Garnish with a bit of extra chopped parsley for a fresh touch.

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Notes

• Customize the cheese blend: While cheddar, Parmesan, and mozzarella work beautifully, feel free to experiment with Gruyère, Monterey Jack, or Fontina for a different flavor twist.
• Add protein: For a heartier version, toss in some cooked bacon bits, shredded chicken, or ground turkey.
• Make it gluten-free: This casserole is naturally gluten-free, so it’s perfect for those avoiding gluten—just double-check your cheese and mayo brands to be safe.

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Watch Out for These Mistakes While Cooking

• Skipping the salting step: Don’t underestimate how much moisture squash and zucchini can hold. Skipping this can lead to a watery casserole.
• Overcooking the vegetables: Remember, they’ll cook more in the oven. Sauté just enough to soften slightly but keep a bit of firmness.
• Using low-fat dairy: Substituting with low-fat versions of sour cream, mayo, or cheese can result in a thinner, less satisfying texture.
• Not draining fully: Even after salting, be sure to thoroughly blot the vegetables. Excess liquid dilutes flavor and can affect texture.
• Baking uncovered too early: If you skip the foil for the first part of baking, the cheese may brown too quickly and dry out before the casserole is fully heated through.
• Forgetting to let it rest: Slicing too soon leads to a mess on the plate. Letting it sit allows it to set properly for clean servings.

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What to Serve With Cheesy Squash and Zucchini Casserole?

This casserole is wonderfully versatile and pairs well with a variety of proteins and side dishes. Whether you’re serving it as a comforting side or a light main, here are some delicious options to round out your meal.

8 Recommendations

1. Grilled Chicken Thighs
   The smokiness from the grill complements the creamy richness of the casserole beautifully.
2. Garlic Butter Steak Bites
   A juicy, savory protein like steak bites balances the cheesy veggies for a hearty dinner.
3. Herb-Crusted Salmon
   Add a fresh, light element with salmon — especially baked or air-fried with lemon and herbs.
4. Roasted Pork Tenderloin
   A lean yet flavorful meat that brings balance without overpowering the delicate casserole.
5. Garden Salad with Vinaigrette
   A crisp salad with a tangy dressing helps cut through the richness and refresh the palate.
6. Fresh Baked Bread or Dinner Rolls
   Perfect for scooping up all the cheesy goodness left behind on the plate.
7. Tomato Basil Soup
   The acidity and brightness of tomato soup make it an unexpected but delicious companion.
8. Balsamic Roasted Vegetables
   A tray of roasted carrots, Brussels sprouts, or sweet potatoes drizzled in balsamic glaze adds depth and color to the plate.

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Storage Instructions

Leftovers of this Cheesy Squash and Zucchini Casserole store well and reheat beautifully, making it a smart make-ahead option.

• Refrigerator: Store in an airtight container or cover the casserole dish tightly with foil. It will keep for up to 4 days in the fridge.
• Freezer: For best texture, freeze before baking. Assemble the casserole, wrap tightly in plastic wrap and foil, and freeze for up to 2 months. When ready to cook, thaw in the fridge overnight and bake as directed.
• Reheating: Reheat individual portions in the microwave for 1–2 minutes or warm the full dish in the oven at 350°F (175°C) for 15–20 minutes, covered loosely with foil to prevent over-browning.

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Estimated Nutrition (per serving, based on 8 servings)

• Calories: 310
• Protein: 11g
• Fat: 26g
• Saturated Fat: 11g
• Carbohydrates: 9g
• Fiber: 2g
• Sugar: 4g
• Cholesterol: 55mg
• Sodium: 480mg

These values are estimates and can vary based on specific brands and portion sizes used.

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Frequently Asked Questions

1. Can I make this casserole ahead of time?

Yes, you can assemble it up to 24 hours in advance and store it in the fridge. Just add 5–10 extra minutes to the baking time if it’s going straight from cold.

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2. Is it okay to skip the salting and draining step?

It’s not recommended. Zucchini and squash hold a lot of water, and skipping this step may result in a watery casserole.

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3. Can I use only zucchini or only squash?

Absolutely. The flavor will be slightly different, but it still works well using just one type of vegetable.

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4. What’s the best cheese substitute if I don’t have cheddar?

Gruyère, Monterey Jack, or a sharp white cheddar make great alternatives that melt beautifully.

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5. Is this recipe vegetarian-friendly?

Yes, it contains no meat. Just be sure your cheese and mayo are vegetarian-safe (some Parmesan uses animal rennet).

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6. Can I add breadcrumbs on top for a crunchy finish?

Definitely! Mix 1/2 cup of panko with a little melted butter and sprinkle over the cheese before baking uncovered.

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7. How do I avoid a soggy casserole?

Thoroughly salt, drain, and pat the squash dry. Also, don’t skip the sauté step — it helps release even more moisture.

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8. Can I make this dairy-free?

It’s possible with dairy-free sour cream, mayo, and cheeses, though the texture and flavor will differ. Look for high-quality alternatives designed for melting.

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Conclusion

This Cheesy Squash and Zucchini Casserole is more than just a side dish — it’s a celebration of fresh ingredients and homestyle comfort. With its bubbling, cheesy top and tender, creamy layers of summer squash and zucchini, it’s a dish that feels both indulgent and nourishing. Whether you’re feeding a family, preparing for a potluck, or just making use of garden bounty, this casserole offers a flavorful, satisfying solution that’s easy to prepare and sure to impress.

Stay tuned for the printable recipe page next!

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