A creamy, cheesy, comforting zucchini casserole with a golden-brown top. The key to avoiding a watery casserole is to remove excess moisture from the zucchini before baking.
Ingredients
For the Casserole
4 medium zucchini, about 5–6 cups, thinly sliced
1 small yellow onion, finely diced
1 tablespoon olive oil or butter
2 cloves garlic, minced
1 cup shredded sharp cheddar cheese
1 cup shredded mozzarella cheese
½ cup grated Parmesan cheese
2 large eggs
½ cup sour cream or plain Greek yogurt
½ teaspoon garlic powder
½ teaspoon Italian seasoning
½ teaspoon salt, plus extra for draining zucchini
¼ teaspoon black pepper
2 oz cream cheese, softened
For the Topping
½ cup shredded mozzarella or cheddar
¼ cup grated Parmesan
½ cup Panko breadcrumbs, optional
1 tablespoon melted butter
1 tablespoon fresh chopped parsley, optional
Equipment
9×13-inch baking dish
Large mixing bowl
Colander
Clean kitchen towel or paper towels
Small skillet
Spatula
Instructions
1. Prepare the zucchini
Wash and dry the zucchini, then slice it into thin, even pieces.
Place the zucchini in a colander and sprinkle lightly with about ½ teaspoon salt. Toss gently and let it sit for 20–30 minutes.
Zucchini contains a lot of water, so this step helps prevent the casserole from becoming watery. After draining, pat the zucchini very dry with paper towels or squeeze it gently in a clean kitchen towel.
2. Preheat the oven
Preheat your oven to 375°F (190°C).
Lightly grease a 9×13-inch baking dish with butter or cooking spray.
3. Sauté the onion and garlic
Heat 1 tablespoon olive oil or butter in a skillet over medium heat.
Add the diced onion and cook for 3–4 minutes, until softened.
Add the minced garlic and cook for another 30–60 seconds. Remove from the heat.
4. Make the creamy cheese mixture
In a large bowl, whisk together:
Eggs
Sour cream or Greek yogurt
Softened cream cheese
Garlic powder
Italian seasoning
Black pepper
Mix until smooth.
Stir in:
1 cup cheddar
1 cup mozzarella
½ cup Parmesan
Cooked onion and garlic
5. Add the zucchini
Add the well-drained zucchini to the cheese mixture.
Gently fold everything together until the zucchini is evenly coated.
6. Fill the baking dish
Transfer the mixture to the prepared baking dish.
Spread it evenly with a spatula.
7. Prepare the topping
For a crispy golden topping, combine:
½ cup shredded cheese
¼ cup Parmesan
½ cup Panko breadcrumbs
1 tablespoon melted butter
Sprinkle evenly over the casserole.
For a low-carb or keto version, simply leave out the breadcrumbs.
8. Bake
Place the casserole in the preheated oven.
Bake uncovered for approximately 30–35 minutes, or until:
The center is set
The edges are bubbling
The zucchini is tender
The cheese is melted
The top is golden brown
If you want a darker, extra-cheesy crust, broil for 1–2 minutes at the end, watching carefully.
9. Rest before serving
Remove from the oven and let it rest for 8–10 minutes before serving.
This allows the creamy cheese mixture to set and makes the casserole easier to portion.
Nutrition Information
Approximate per serving, based on 8 servings and including Panko:
Calories: ~300
Protein: ~16 g
Total Fat: ~21 g
Saturated Fat: ~11 g
Carbohydrates: ~13 g
Fiber: ~2 g
Net Carbs: ~11 g
Sugar: ~5 g
Sodium: ~550 mg
Calcium: ~330 mg
Nutrition can vary depending on the exact cheeses, sour cream/Greek yogurt, and breadcrumbs used.
Nut Information
Tree nuts: None
Peanuts: None
Coconut: None
Sesame: None in the basic recipe
Important: If preparing this for someone with a serious food allergy, check the labels on cheese, breadcrumbs, seasonings, and other packaged ingredients for possible cross-contact.
Dietary Information
Vegetarian: Yes
High protein: Moderate; can be increased
Low carb: Yes, especially without breadcrumbs
Keto-friendly: Yes, when breadcrumbs are omitted
Gluten-free: Yes if using certified gluten-free ingredients and gluten-free breadcrumbs, or no breadcrumbs
Nut-free: Yes based on the listed ingredients, subject to packaged-product labels
High-Protein Variation
To make this casserole more protein-rich, add:
1 cup cooked shredded chicken, or
1 cup low-fat cottage cheese blended into the creamy mixture
You can also replace sour cream with plain Greek yogurt.
Vegetable Variations
You can add:
Diced bell peppers
Mushrooms
Spinach
Yellow squash
Broccoli
Chopped tomatoes, preferably well-drained
Avoid adding too many watery vegetables unless you drain them first.
Cheese Variations
Try:
Cheddar + mozzarella
Monterey Jack + Parmesan
Gruyère + mozzarella
Pepper Jack + cheddar
Provolone + Parmesan
A combination of melting cheese and Parmesan gives the casserole both creaminess and a flavorful browned top.
Storage
Store leftovers in an airtight container in the refrigerator for 3–4 days.
Reheating
Oven: 350°F (175°C) for 10–15 minutes
Microwave: 1–2 minutes per serving, until hot
The oven generally gives you a better texture and helps the topping crisp again.
Frequently Asked Questions
Q: Why is my zucchini casserole watery?
A: Zucchini naturally contains a lot of water. Salting, draining, and thoroughly drying the zucchini before mixing it into the casserole is one of the most important steps.
Q: Can I make it without breadcrumbs?
A: Yes. Simply omit the Panko. The casserole will still have a delicious cheesy top and will also be lower in carbohydrates.
Q: Can I use frozen zucchini?
A: Yes, but fresh zucchini is preferable. If using frozen, thaw completely and squeeze out as much water as possible before adding it.
Q: Can I use Greek yogurt instead of sour cream?
A: Yes. Plain, unsweetened Greek yogurt works very well and adds extra protein.
Q: Can I prepare this ahead of time?
A: Yes. Assemble the casserole, cover it, and refrigerate it for several hours. Add the crispy topping shortly before baking for the best texture.
Q: Can I freeze Cheesy Zucchini Casserole?
A: It is not ideal for freezing because zucchini releases additional water and creamy cheese sauces can change texture after thawing. Fresh or refrigerated is best.
Q: What should I serve with it?
A: It pairs especially well with grilled chicken, roasted chicken, baked fish, steak, turkey, or a fresh green salad.
Q: How do I make it extra cheesy?
A: Add another ½ cup of shredded mozzarella or cheddar during assembly and another small handful on top before baking.
Q: Can I make it keto?
A: Yes. Use full-fat cheese and sour cream or cream cheese, and leave out the Panko breadcrumbs. Cheesy zucchini casseroles are commonly adapted as low-carb or keto dishes.
Q: Can I make it without eggs?
A: Yes, although the texture will be softer. You can increase the cream cheese and use a suitable egg substitute designed for baking.
Serving Suggestion
Serve warm with a sprinkle of fresh parsley and a little extra Parmesan. For a complete meal, pair it with grilled chicken or salmon and a simple cucumber-tomato salad.
Servings: 8
Prep Time: 25–30 minutes
Cook Time: 30–35 minutes
Resting Time: 10 minutes
Total Time: About 1 hour 10 minutes
With years of experience in restaurant research and local SEO, Sara creates accurate, user-friendly guides that work for both people and search engines. Her goal is to help users go from search results to their nearest restaurant or menu choice with as few clicks as possible.
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