Irresistibly Creamy Cheesy Zucchini Casserole: Your Go-To Summer Squash Recipe
Discover the ultimate way to enjoy your summer harvest with this incredibly creamy and cheesy zucchini casserole. Featuring tender slices of fresh zucchini, lovingly baked with a blend of savory cheeses, aromatic onion, and fragrant garlic, this dish is pure comfort food. Finished with a delightful topping of crisp, golden panko breadcrumbs, it emerges from the oven bubbling and perfectly golden. This easy-to-make casserole is sure to become a cherished favorite, perfect for weeknight dinners or special gatherings.
Why This Cheesy Zucchini Casserole Recipe Is a Must-Try
When summer brings an abundance of garden squash, this easy zucchini casserole is the perfect solution. It’s not just a dish; it’s a celebration of fresh, seasonal ingredients transformed into creamy, cheesy goodness. What makes this recipe truly stand out is its delightful texture combination: tender, flavorful zucchini slices enveloped in a rich, velvety cheese sauce, all crowned with a crispy panko breadcrumb topping that adds an irresistible crunch. You can even skip the breadcrumbs for a delicious low-carb side dish, making it incredibly versatile for any dietary preference.
Often referred to as “zucchini au gratin,” this casserole shares many similarities with its potato counterpart, scalloped potatoes. Both dishes feature thinly sliced vegetables baked in a creamy, cheesy sauce until golden and bubbly. The key difference here is the use of fresh zucchini, which provides a lighter, more vibrant flavor profile, perfect for warmer months. The method of preparation ensures that the zucchini remains tender without becoming watery, a common concern when cooking with this moisture-rich vegetable. This recipe is simple enough for a weeknight but impressive enough for entertaining, making it a reliable crowd-pleaser that everyone will ask for again and again.
Gather Your Ingredients for This Easy Zucchini Casserole
To create this magnificent zucchini casserole, you’ll need a selection of fresh and pantry staples. While all measurements and detailed instructions are provided in the printable recipe card at the end of this post, here’s an overview of the key components that come together to form this delightful dish.
Detailed Ingredient Information and Expert Substitution Tips
Understanding each ingredient’s role and knowing your options for substitutions can elevate your cooking experience and ensure a successful dish every time. Here’s a closer look at what goes into our creamy zucchini casserole:
- ZUCCHINI – This summer squash is the star of our casserole. Zucchini has a naturally high water content, which can sometimes lead to a watery casserole if not properly prepared. To prevent this, we lightly sauté the sliced zucchini before baking. This crucial step helps draw out excess moisture, concentrating its flavor and ensuring a tender yet firm texture in the final dish. Sautéing also gives the zucchini a slight char and a beautiful golden crust, adding another layer of flavor. When selecting zucchini, look for firm, vibrant green squash without blemishes. For slicing, aim for consistent discs, about 1/4 inch thick, for even cooking. You can easily substitute zucchini with yellow squash, or use a delightful mixture of both for added color and a subtle difference in flavor.
- CHEESE – The heart of any good casserole! We recommend a robust combination of both cheddar and Monterey Jack cheese for optimal flavor and melt. Cheddar brings a sharp, savory depth, while Monterey Jack offers a creamy, mild flavor and excellent melting properties, creating that perfect gooey texture. Feel free to experiment with different types of cheddar – old, mild, or sharp – depending on your preference for intensity. For Monterey Jack, excellent substitutes include Havarti, which is incredibly creamy and melts beautifully, Gouda for a slightly nutty and buttery flavor, or Muenster cheese, known for its smooth texture and mild, buttery taste. Always aim for freshly shredded cheese if possible, as pre-shredded varieties often contain anti-caking agents that can affect how smoothly they melt.
- MAYO – Mayonnaise is the secret ingredient that gives this casserole its luxurious, creamy texture. It creates a rich, emulsified base that holds all the flavors together beautifully. We strongly advise against leaving it out, as it is integral to the casserole’s signature creaminess and binds the ingredients without needing a traditional béchamel sauce. If you’re concerned about richness, you could try a light mayonnaise, but the full-fat version delivers the best results. Its slight tang also helps balance the richness of the cheese and the sweetness of the zucchini.
- **ONION & GARLIC** – These aromatic powerhouses form the foundation of flavor for our casserole. Finely chopped onion and minced garlic are sautéed with the zucchini, infusing the entire dish with their savory, pungent notes. Use fresh garlic cloves for the best flavor, and aim for a medium-sized yellow or white onion.
- **ITALIAN SEASONING** – A convenient blend of dried herbs like oregano, basil, thyme, and rosemary, Italian seasoning adds a classic, warm, and herbaceous touch that complements the vegetables and cheese beautifully. Adjust the amount to your taste.
- **SEA SALT** – Essential for enhancing all the flavors. Zucchini benefits greatly from proper seasoning.
- **PANKO BREADCRUMBS** – These Japanese-style breadcrumbs are lighter and flakier than traditional breadcrumbs, resulting in an exceptionally crisp and golden topping when baked. They provide a wonderful textural contrast to the soft, creamy casserole below.
- **UNSALTED BUTTER** – Melted butter is combined with the panko breadcrumbs to ensure they toast evenly and achieve a rich, golden-brown color and irresistible crunch. Using unsalted butter gives you more control over the overall saltiness of the dish.
- **EXTRA VIRGIN OLIVE OIL** – Used for sautéing the vegetables, adding a light, fruity flavor and helping to develop that initial crust on the zucchini.
Step-by-Step: How to Make This Delicious Zucchini Casserole
These step by step photos and instructions are here to help you visualize how to make this recipe. You can Jump to Recipe to get the printable version of this recipe, complete with measurements and instructions at the bottom.
- Preheat your oven to 350F (175°C). Prepare a 7×11 inch baking dish (approximately 2 quarts) by thoroughly coating it with non-stick cooking spray. This crucial step prevents the cheesy casserole from sticking and makes cleanup much easier. Set the prepared dish aside.
- In a large skillet, heat the extra virgin olive oil over medium heat. Add the sliced zucchini, chopped onion, minced garlic, Italian seasoning, and sea salt. Sauté this mixture for about 5 minutes, stirring occasionally, until the vegetables begin to soften slightly and the onion becomes translucent. This step is vital for reducing the zucchini’s water content and concentrating its flavor, preventing a soggy casserole.
- Once the vegetables are softened, remove the skillet from the heat. Stir in the cheddar cheese and 2 ½ cups of the Monterey Jack cheese until they begin to melt into the warm zucchini mixture. Then, add the mayonnaise and mix everything until it’s thoroughly combined, creating a rich and creamy base.
- Transfer the creamy, cheesy zucchini mixture evenly into the prepared baking dish. Once spread, sprinkle the remaining 1 cup of Monterey Jack cheese over the top. This layer of cheese will create a beautiful golden crust when baked.
- Cover the baking dish tightly with aluminum foil. Bake for 25-30 minutes, or until the casserole is hot and bubbly. For an expert tip: spray the underside of the foil with non-stick cooking spray before covering to prevent the melting cheese from sticking to it.
- While the casserole is baking and just before you’re ready to remove it from the oven, melt the unsalted butter in a small bowl. Add the panko breadcrumbs to the melted butter and stir to coat them evenly. This ensures a golden, crispy topping. Evenly sprinkle this buttery panko mixture over the top of the hot, bubbly casserole.
- Move your oven rack to the second highest level. Return the casserole to the oven and broil, uncovered, for a short period until the panko topping is beautifully golden brown and crisp. This step happens quickly, so keep a very close eye on it to prevent burning!
- Carefully remove the casserole from the oven. For a fresh touch and pop of color, garnish with some freshly chopped parsley before serving. Let it cool for a few minutes before diving in to allow the cheese to set slightly. Enjoy!
Frequently Asked Questions & Expert Tips for Zucchini Casserole
Yes, this zucchini casserole freezes quite well, making it an excellent make-ahead option. To freeze a fully baked and cooled casserole, wrap it tightly first in plastic wrap, then in a layer of heavy-duty aluminum foil. This double wrapping helps prevent freezer burn. It can be stored in the freezer for up to 3 months. When you’re ready to enjoy it, thaw the casserole overnight in the refrigerator, or at room temperature for several hours, then bake it in a 350F oven until heated through and bubbly, which usually takes 20-30 minutes. While you can freeze an unbaked casserole using the same method, be aware that the zucchini might release more water upon thawing, potentially resulting in a slightly more watery texture once baked.
Any leftover zucchini casserole should be stored promptly in an air-tight container in the refrigerator. It will stay fresh and delicious for 3-4 days. To reheat, you can place individual servings in the microwave, or for larger portions, reheat in a 350F (175°C) oven for 10-15 minutes, or until thoroughly warmed through. If the panko topping has lost some of its crispness, you can briefly broil it for a minute or two (watch carefully!) to regain its crunch.
The most important step to prevent a watery casserole is to properly sauté the zucchini before mixing it with the other ingredients. As zucchini has a high water content, lightly sautéing it for 5 minutes as directed in the recipe draws out much of that moisture. You can also lightly salt the sliced zucchini and let it sit for 15-20 minutes, then gently blot it dry with paper towels before sautéing. This extra step can further reduce moisture, ensuring a firm, flavorful casserole.
Yes, this casserole is an excellent make-ahead dish. You can assemble the entire casserole (up to the point of adding the panko topping) and store it covered in the refrigerator for up to 24 hours. When ready to bake, let it sit at room temperature for about 30 minutes before baking, then follow the baking instructions, adding the panko topping just before the final broiling stage. This makes it perfect for meal prepping or entertaining.
Absolutely! While this recipe is fantastic as a vegetarian side, you can easily turn it into a heartier main dish by adding cooked meat. Cooked ground beef, turkey, or crumbled sausage would be delicious additions. Simply brown and drain your chosen meat, then stir it into the zucchini and cheese mixture before transferring it to the baking dish. Cooked, shredded chicken would also work wonderfully. This addition transforms the casserole into a complete meal.
A 7×11 inch (or 2-quart capacity) baking dish is ideal for this recipe, ensuring the perfect depth and surface area for that golden, bubbly top. However, a standard 8×8 inch square dish or a smaller 9×13 inch rectangular dish could also work. If using a larger dish, the casserole will be thinner and might bake a bit faster, so keep an eye on it. Conversely, a smaller, deeper dish may require a longer baking time to ensure it cooks through evenly.
Delightful Serving Suggestions for Zucchini Casserole
This creamy cheesy zucchini casserole is incredibly versatile and makes an exquisite addition to almost any meal. It can shine as a comforting side dish or even take center stage as a light vegetarian main course. Its rich flavor and satisfying texture pair beautifully with a wide array of proteins, from perfectly grilled chicken breasts to juicy roasted beef, tender pork chops, or delicate flaky fish. For a truly balanced meal, consider serving it alongside a fresh, crisp green salad with a light vinaigrette to cut through the richness, or some crusty bread to soak up every last bit of that amazing sauce.
If you’re looking for an even lighter or lower-carb option, simply omit the panko breadcrumbs and butter topping. The casserole remains wonderfully flavorful and creamy, offering a delicious, guilt-free side that’s bursting with savory goodness. This makes it an ideal choice for those following specific dietary plans or simply looking to reduce their carb intake without sacrificing taste. Whether for a casual family dinner, a festive holiday meal, or a potluck gathering, this zucchini casserole is guaranteed to impress.
Explore More Delicious Zucchini Recipes
If you find yourself with an abundance of zucchini or simply can’t get enough of this versatile vegetable, be sure to explore these other fantastic recipes. From grilling to sautéing and creative snacks, there’s a zucchini dish for every occasion:
- Grilled Zucchini
- Sauteed Zucchini
- Zucchini Pizza Bites
- How To Make Zucchini Noodles
- Grilled Corn and Zucchini Salad with Feta
- Zucchini Fritters
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Zucchini Casserole
IMPORTANT – There are often Frequently Asked Questions within the blog post that you may find helpful. Simply scroll back up to read them!
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Ingredients
- 1 ½ Tablespoons extra virgin olive oil
- 4 medium zucchinis sliced round, about 6 cups, 1/4 inch thick
- 1 medium onion chopped
- 2 large garlic cloves minced
- 1 teaspoon Italian seasoning
- 1 teaspoon sea salt
- 3 ⅓ cups Monterey Jack cheese freshly shredded, divided
- 1 ½ cups cheddar cheese freshly shredded, old, mild, or sharp
- 1 cup mayonnaise
- 1 cup panko breadcrumbs
- 2 Tablespoons unsalted butter melted
- fresh chopped parsley optional, for garnish
Things You’ll Need
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2 quart baking dish
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Large skillet
Before You Begin
- For best results, ensure your zucchini is lightly sautéed to draw out moisture and prevent a watery casserole.
- Freshly shredded cheese melts smoother and tastes better than pre-shredded varieties.
- The mayonnaise is key for the creamy texture; do not skip it!
- This casserole is freezer-friendly: wrap baked and cooled portions tightly and freeze for up to 3 months.
- For a delicious lower-carb option, simply omit the panko breadcrumbs and butter topping. This reduces the carbohydrates per serving significantly.
Instructions
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Preheat your oven to 350F (175°C). Prepare your 7×11 inch (2 quart) baking dish by generously coating it with non-stick cooking spray, ensuring all surfaces are covered to prevent sticking.
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In a large skillet, heat the extra virgin olive oil over medium heat. Add the sliced zucchini, chopped onion, minced garlic, Italian seasoning, and sea salt. Sauté the vegetables for approximately 5 minutes, or until the zucchini begins to soften and release some moisture, and the onion becomes translucent.
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Remove the skillet from the heat. Stir in the cheddar cheese and 2 ½ cups of the Monterey Jack cheese until they are well combined and start to melt. Add the mayonnaise to the mixture and mix thoroughly until all ingredients are evenly incorporated and a creamy sauce forms.
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Carefully transfer the cheesy zucchini mixture into the prepared baking dish, spreading it evenly. Sprinkle the remaining 1 cup of Monterey Jack cheese over the top of the casserole, creating a delicious upper layer.
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Cover the baking dish tightly with aluminum foil. For a useful tip: spray the underside of the foil with non-stick cooking spray to prevent the melting cheese from sticking. Bake for 25-30 minutes, or until the casserole is hot and bubbling around the edges.
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Just before the casserole finishes baking, melt the unsalted butter in a small bowl. Add the panko breadcrumbs to the melted butter and stir until they are fully coated. Remove the foil from the casserole, and then evenly sprinkle the buttered panko mixture over the top.
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Move your oven rack to the second highest position. Return the uncovered casserole to the oven and broil for a short time until the panko topping turns golden brown and becomes crisp. This step can happen very quickly, so keep a constant watch to avoid burning!
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Remove the casserole from the oven. Garnish with fresh chopped parsley if desired, and let it cool for a few minutes before serving. Enjoy your homemade creamy cheesy zucchini casserole!
Nutrition
The recipes on this blog are tested with a conventional gas oven and gas stovetop. It’s important to note that some ovens, especially as they age, can cook and bake inconsistently. Using an inexpensive oven thermometer can assure you that your oven is truly heating to the proper temperature. If you use a toaster oven or countertop oven, please keep in mind that they may not distribute heat the same as a conventional full sized oven and you may need to adjust your cooking/baking times. In the case of recipes made with a pressure cooker, air fryer, slow cooker, or other appliance, a link to the appliances we use is listed within each respective recipe. For baking recipes where measurements are given by weight, please note that results may not be the same if cups are used instead, and we can’t guarantee success with that method.