Cheesy Zucchini Casserole
This tasty zucchini casserole has it all—creamy cheesy sauce, lots of tender zucchini, and a buttery crunchy topping.
This cheesy zucchini casserole recipe is the perfect side dish for a family meal or special occasion dinner. From the creamy, cheesy filling to the cheddar and buttery breadcrumb topping, it is bound to please. With a combination of zucchini, creamy cheese sauce, and a buttery breadcrumb topping, my cheesy zucchini casserole is both hearty and versatile. It’s an excellent side dish to pair with your favorite entrees. It pairs nicely with hamburger steaks, pork chops, roasted chicken, and baked ham.
The star of the dish is zucchini, a mild, adaptable vegetable that takes on the flavors of its surrounding ingredients. The tender-cooked zucchini and onions are combined with an easy, seasoned cheese sauce. The casserole is topped with more cheese and buttery panko crumbs, making it savory, rich, and crunchy.
I used mild cheddar cheese for its excellent melting properties, but feel free to use another cheese. Gruyère would work well, or choose sharp cheddar or a Monterey Jack blend.
Add the casserole to your weekly or monthly menu rotation, and if zucchini is in season, all the better. If you don’t have an abundance of zucchini in your garden, you’ll find it’s readily available and reasonably priced in the supermarket and farmers’ markets.
What You’ll Like About This Recipe
- Creamy, cheesy comfort without being too heavy. The sauce is rich enough to feel indulgent but still lets the zucchini shine. The flour-thickened base keeps it silky rather than overly dense.
- A great way to use lots of zucchini. Six cups cook down beautifully, becoming tender and flavorful without getting mushy. It’s an ideal recipe for gardeners or summer produce hauls.
- Crowd-pleasing flavor and texture. The buttery panko topping adds crunch to balance the creamy interior, and the melted cheddar brings everything together.
- Simple ingredients and easy steps. Everyday staples like milk, butter, flour, and cheese transform zucchini into a satisfying side dish with minimal effort.
- Versatile enough for weeknights or holidays. It pairs effortlessly with chicken, ham, pork, or grilled dishes and holds its own on a Thanksgiving or Christmas table.
Ingredient Notes
- Zucchini – Choose medium zucchini for consistent slices and better texture. Very large zucchini may contain excess moisture; scrape out overly large seeds if needed.
- Onion – Diced onion sautés quickly and adds depth. Yellow or sweet onions both work, but avoid red onions, which can discolor the sauce.
- Cheddar cheese – Mild cheddar melts smoothly, but sharp cheddar offers more pronounced flavor. A blend of cheddar and Monterey Jack also works well.
- Milk – Whole milk gives the sauce body. Low-fat milk works but may produce a slightly thinner sauce.
- Panko crumbs – Provide a light, crisp crust. Regular breadcrumbs can be substituted but won’t be quite as crunchy.
- Mustard powder – Enhances the cheddar flavor without making the dish taste like mustard. It’s optional but highly recommended.
How to Make the Casserole
- Prepare the baking dish and melt butter in the skillet. The melted butter adds richness and helps the zucchini sauté gently without browning.
- Cook the onions until just softened, then add the zucchini and cover. The steam created under the lid softens the zucchini quickly while helping it retain moisture without turning mushy.
- Transfer the vegetables to the baking dish, using a slotted spoon to avoid adding excess liquid. This prevents the casserole from becoming watery.
- Make the cheese sauce by creating a simple roux with butter and flour. Add the milk gradually, whisking to avoid lumps, then season and stir in part of the cheese. The sauce should thicken just enough to cling to the vegetables.
- Pour the sauce over the zucchini and onion mixture, letting it seep into the spaces between slices.
- Combine melted butter with panko crumbs for the crisp topping, then layer on the remaining cheese and crumbs.
- Bake until the top is golden and the edges bubble, ensuring a crisp crust and a fully set center.
Pro Tips
- Drain any excess moisture from the zucchini before adding the sauce; too much liquid can thin the casserole.
- Slice the zucchini evenly so it cooks uniformly and stays tender.
- Use freshly shredded cheese for the best melt and smoothest sauce.
- Let the casserole rest for a few minutes before serving so the layers settle.
- Brown the topping briefly under the broiler if you want a deeper golden crust.
Recipe Variations
- Protein: Make it a hearty main dish with the addition of browned ground beef or sausage, or some diced leftover ham or chicken.
- Spicy Twist: Add some minced jalapeño peppers or use pepper jack cheese for a pleasant bit of heat.
- Herbs: Mix in fresh chopped herbs, such as basil, thyme, or parsley.
- Italian: Add a drizzle of marinara sauce and use fresh mozzarella for the topping.
Serving Suggestions
- Serve alongside roasted chicken, pork roast, grilled steaks, or baked ham.
- Add a bright green salad or steamed vegetables to balance the creaminess.
- Pair with rice, quinoa, or crusty bread for a complete meal.
- Choose this casserole as a holiday side dish; it complements turkey and stuffing beautifully.
How to Store
- Refrigerate leftovers in an airtight container for up to 3 days. The topping softens slightly but the flavors remain excellent.
- Freeze tightly wrapped portions for up to 2 months; thaw in the refrigerator before reheating.
- Reheat in the oven or air fryer until warmed through and the topping is crisp again. Avoid the microwave if possible, as it softens the crust.
Cheesy Zucchini Casserole
Ingredients
- 1/2 cup unsalted butter, (4 ounces), divided
- 3/4 cup diced onion
- 6 cups zucchini, sliced, about 2 pounds
- 2 tablespoons flour
- 1 cup whole milk
- 3/4 teaspoon fine sea salt, or to taste
- 1/4 teaspoon mustard powder
- 1/4 teaspoon freshly ground black pepper
- 1 1/2 cups mild cheddar cheese, shredded , divided
- 1 cup panko breadcrumbs
Instructions
- Heat the oven to 350°F and butter a 1 1/2-quart baking dish.
- Melt 4 tablespoons of butter in a large skillet over medium heat. Add the chopped onion and cook, stirring, for 2 minutes. Add the sliced zucchini, cover the pan, and reduce the heat to low. Cook for 8 minutes or until the zucchini is just tender. Remove the zucchini and onions to the baking dish with a slotted spoon.
- Wipe out the skillet, add 2 tablespoons of butter, and melt it over medium heat, then stir in the flour. Cook for 2 minutes, then gradually add the milk. Taste and add the salt, mustard powder, black pepper, and 1/2 cup of the cheese. Cook, stirring, until hot and thickened. Pour the mixture over the zucchini mixture in the baking dish.
- Melt the remaining 2 tablespoons of butter and toss with the panko crumbs.
- Sprinkle the remaining cheese over the casserole, followed by the buttered panko crumbs.
- Bake for 25 minutes or until the topping is browned and the casserole is bubbling around the edges.
Nutrition
Disclaimer:
Our nutritional information is based on a third-party application that analyzes the ingredients list to determine the values. The information is meant to be helpful, but should be considered an estimate. Values may differ depending on measurements, brands, serving variations, and database availability.
