This Garlic Parmesan Zucchini Casserole is an easy side dish recipe that pairs beautifully with just about any family meal! The old fashioned zucchini casserole recipe features fresh, shredded zucchini, garlic, and onion, with three types of cheese and a buttery, Parmesan breadcrumb topping. Serve the cheesy dish with grilled chicken, oven-fried pork chops, steak or shrimp. It's versatile, and always a hit!
How to Make Garlic Parmesan Zucchini Casserole | 1-Minute Video
This cheesy zucchini casserole recipe has quickly become a favorite among the boys in my house! I'm telling you: if you want to get your kids (or your husband) to eat some green vegetables, then this is the recipe for you. The zucchini is mild, it's baked with three different kinds of cheese, and it's finished with a buttery Parmesan breadcrumb topping. What's not to love?!
Ingredients
This is a quick overview of the ingredients that you'll need for an easy zucchini casserole. As always, specific measurements and complete cooking instructions are included in the printable recipe box at the bottom of the post.
- Zucchini: this freshly-grated veggie is the star of the show! You'll need a total of 4 cups grated, which is equivalent to approximately 3 ½ medium zucchinis.
- Salt: enhances the flavors in the dish and helps to draw out moisture from the zucchini so that you don't end up with a watery casserole.
- Onion and garlic: for more flavor.
- Eggs: give the casserole structure.
- Parmesan, mozzarella and cheddar cheese: three different types of grated cheese add a variety of flavors to the casserole.
- Panko breadcrumbs and melted butter: combine with Parmesan to form the crispy, golden brown topping.
How do you keep squash casserole from getting watery?
Zucchini and other summer squash naturally holds a lot of water, so you'll probably notice that the vegetable releases a lot of water as it cooks. This can be a problem when adding squash to casseroles, bakes, and sauces, since the vegetables can water down the sauce or casserole, resulting in a bland flavor and undesirable texture.
If you sprinkle the shredded zucchini with salt and allow it to sit in a colander for about 10 minutes, the salt draws out a lot of moisture from the vegetable before you add it to the casserole.
TIP: In order to make sure that I get most of the water out of the zucchini (and avoid a watery casserole), I like to wrap the zucchini in a dish towel. Squeeze it and wring it out multiple times while it's in the towel -- you will be shocked by how much liquid comes out!
How to Make Zucchini Casserole
This cozy, family-friendly vegetable side dish comes together easily without any special cooking skills. Just remember to allow enough time to let the zucchini sit in the colander before squeezing it dry and adding it to the casserole.
- Place zucchini in a colander, sprinkle with salt, and allow to sit for about 10 minutes (this will help draw out some of the water from the zucchini). After 10 minutes, squeeze out the moisture from the zucchini.
- Combine zucchini, onion, garlic, eggs, ½ cup Parmesan cheese, mozzarella cheese, and cheddar cheese in a small, greased baking dish.
- Bake uncovered in a 375° F oven for 20 minutes.
- Make the topping by combining melted butter with breadcrumbs and additional Parmesan cheese.
- Sprinkle the breadcrumbs over the casserole and return the dish to the oven.
- Bake for about 5-10 more minutes, or until the top is golden brown and crispy.
What to Serve with Easy Zucchini Casserole
This versatile casserole pairs nicely with just about any meat, seafood or pasta. Here are a few ideas to serve with a cheesy zucchini casserole:
- Grilled Salmon or Grilled Scallops
- Marinated Grilled Shrimp
- Grilled Chicken, Oven-Fried Chicken, Whole Roasted Chicken, or Roasted Chicken Thighs with Garlic and Herbs
- Grilled Flank Steak, Cast Iron Skillet Filet Mignon, or Grilled Steak Tips
- Grilled Pork Chops, Pork Tenderloin, or Pulled Pork
- Lemon Chicken Piccata, Pasta with Sausage and Spinach, or Shrimp Scampi
Is this casserole gluten free?
You can easily make this zucchini casserole gluten-free by using gluten-free breadcrumbs. If you want to add a little more fiber and nutrition to the dish, use whole wheat breadcrumbs (which are not gluten-free).
Storage
Store leftover zucchini casserole in an airtight container in the refrigerator for up to 3 days. Reheat in a 350° F oven just until warmed through.
You can freeze the leftovers; however, this is not my preference because the zucchini will hold a lot of water, negatively impacting the texture and taste when thawed.
Recipe Variations
- I've used three different types of cheese here: Parmesan, mozzarella and cheddar. You can substitute with an equal amount of any of your favorite cheeses -- or stick to just mozzarella or just cheddar.
- Use a combination of yellow squash and zucchini, or replace all of the zucchini with yellow squash.
- To serve a larger family, double all of the ingredients and bake the casserole in a larger dish. You may need to add a few extra minutes to the total cooking time, but the rest of the instructions remain the same.
Tips for the Best Zucchini Casserole Recipe
- I just use a handheld box grater to shred my zucchini, but you can also put it through a food processor if you prefer.
- Make sure that you drain the zucchini before adding it to your casserole. To do so, sprinkle it with salt, let it sit in a colander for about 10 minutes, and then wring it out in a dish towel.
- Garnish the dish with fresh herbs (such as chopped fresh parsley) for a bright burst of color and flavor.
What can you do with a ton of zucchini?
Here are a few of our favorite ways to take advantage of a bounty of fresh zucchini:
- Zucchini Fritters
- Greek Yogurt Chocolate Zucchini Cake
- Morning Glory Farm Zucchini Bread
- Skillet Pork Chops with Zucchini and Squash
- Crispy Zucchini Fries
- Easy Stuffed Zucchini Boats
Garlic Parmesan Zucchini Casserole
Ingredients
- 4 cups grated zucchini I used about 3.5 medium zucchinis
- ½ teaspoon salt
- ½ cup finely diced onion I like to use frozen diced onion as a shortcut
- 1 tablespoon minced garlic
- 2 eggs
- ½ cup grated Parmesan cheese plus an additional 2 tablespoons
- 1 cup shredded mozzarella cheese
- ½ cup shredded cheddar cheese
- ½ cup Panko breadcrumbs
- 2 tablespoons melted butter
Instructions
- Preheat oven to 375 degrees F. Spray a small baking dish with cooking spray and set aside (I used a dish that was 8-in x 5-in, but an 8-inch square pan will also work).
- Place zucchini in a colander, sprinkle with salt, and allow to sit for about 10 minutes (this will help draw out some of the water from the zucchini). After 10 minutes, squeeze out moisture from the zucchini. TIP: In order to make sure that I get most of the water out of the zucchini (and avoid a runny casserole), I like wrap the zucchini in a dish towel. Squeeze it and wring it out multiple times while it's in the towel -- you will be shocked by how much liquid comes out!
- In the prepared dish, combine zucchini, onion, garlic, eggs, ½ cup Parmesan cheese, mozzarella cheese, and cheddar cheese. I like to use my hands to make sure that it’s all completely combined, and then gently press the mixture evenly into the prepared dish.
- Bake uncovered for 20 minutes.
- Meanwhile, in a small bowl, pour melted butter over breadcrumbs and 2 tablespoons of Parmesan cheese. Stir until completely combined.
- After 20 minutes, remove zucchini from the oven. Sprinkle buttered breadcrumbs over the zucchini and return the dish to the oven. Continue baking for about 5-10 more minutes, or until the top is golden brown and crispy.
Video
Notes
- I just use a handheld box grater to shred my zucchini, but you can also put it through a food processor if you prefer.
- Make sure that you drain the zucchini before adding it to your casserole. To do so, sprinkle it with salt, let it sit in a colander for about 10 minutes, and then wring it out in a dish towel.
- Garnish the dish with fresh herbs (such as chopped fresh parsley) for a bright burst of color and flavor.
Nutrition
This post was originally published in February, 2017. It was updated in May, 2021.
Christiane
Probably my ever best dish, I have made it now for forty years non stop....I don ‘ t put eggs, so it is lighter ....I usually slice the courgettes very thin in the magimix...then steam them.....I always make a big amount so I can freeze it after baking...in the baking dish...and reheat it in a hot oven...love it when the rice gets crispy at the bottom.....I also add leftovers green like kale....my mum add cooked tomatoes in the mix...she likes it moist....
Cheers
Christiane
Blair
Sounds perfect, Christiane!
Christine
An easy and truly delicious recipe. I love zucchini and was glad to have a new way to prepare it. This is a perfect dish to bring to gatherings - I can’t wait! I know it will be a hit! I served it with grilled chicken sausage in a little marinara sauce and they went together wonderfully. Thank you for the great recipe!
Blair
Thank you, Christine! I'm so glad that you liked it and that you'll share it with friends and family, too. 🙂
Valentina Rossi
I made this tonight with a couple of minor changes. I did not have cheddar, so I substituted smoked gruyere, which added a cheesy, smoky note to the mix. I also dusted the top with (hot) smoked Spanish paprika, which added a hint of spiciness but without being overpowering.
Finally, because i hadn't read the directions all the way through before putting the casserole dish in the oven, i topped it with the crumb mixture before putting it in to bake for the first time. I was worried the top would burn after 35 minutes, but it was perfect.
I will definitely make this again, playing around with the cheeses and spices. It's very versatile.
Blair
Your version sounds delicious, Valentina! Thanks for your notes, and so glad that you enjoyed it!
Cary
Wow! This is fabulous! My husband loved it as well. I used 2 zucchini and 2 yellow squash and the colors were beautiful
Blair
Thank you, Cary!
Patricia Ann Haag
Maybe it is me, buy the onions were too crunchy - should I have sauteed them first? It was just okay - sorry!
Blair
Hi, Patricia! You can certainly saute them first next time, but I haven't ever found them to be crunchy in this dish. Maybe if you chop them a bit finer it would help? Or even grate them? Sorry it wasn't a hit!
Tara
CN you use frozen shredded zucchini?
Blair
Hi, Tara! I've never tried that, but I think it would work as long as you really strain the liquid from the thawed zucchini first. Let me know if you give it a shot!
Tami Ramos
I sauté mine and it comes out amazing
Karen
I made this for the first time today. It's definitely a keeper since my garden produces SO much zucchini! I made it exactly as the recipe and the family loved it. Squeezing the grated zucchini in a towel was genius. All the moisture was gone so the casserole came out perfect and not watery. I also appreciate the size of the casserole. It's perfect for us empty nester- so many other recipes make a huge 13 x 9 dish and that's too much for us. Thank you for a delicious recipe!
Blair
Awesome! Thanks, Karen! I hope that you enjoy it with your fresh zucchini all summer long. 🙂
Susan Mercurio
Yes, you squeeze out the water when you salt the zucchini, but you are also squeezing out all of the water-soluble vitamins, such as Vitamin C and all the B vitamins.
I don't know why you eat, but I eat for nutrition.
What I do to keep the casserole from getting soggy while saving the vitamins is to put a layer of uncooked pasta in the bottom of the dish and then add the zucchini and the rest of the ingredients.
Dorene Kordal
This is so delicious and easy to make. Will make this over and over!
Blair
Thank you, Dorene!
Wannabe Chef Dennis
I was wondering what the heck to do with all the remaining zucchini I hand shredded while assisting the wife make her self professed Worlds Greatest Zucchini Bread. All kidding aside - it is very good bread.
I followed your recipe as best I could with the ingredients I had on had, all the while substituting where I saw fit AKA: “just winging it”. I used badia seasoning for the salt. I sprayed my 9x13 Pyrex with Pam and sprinkled it with salt, pepper and garlic powder prior to adding the mix. I used Amish candy onion, all cheddar cheese, and sprinkle Parmesan/Romano. I added about 1/4 finely chopped green pepper, a jar of drained and mushrooms and about a cup of chopped seasoned chicken breast.
Yum Yum! I’ll be keeping this recipe in my arsenal. Once the wife tastes it, I am sure she will claim the recipe as her own and expect accolades from All when she makes it! Ha ha
Blair
Hah! I'm glad that you found a good way to use up the rest of the zucchini, Dennis! Now I'm curious about your wife's bread! 🙂
Brenda
This is our new all time favorite zucchini recipe. Only thing I did different was using Italian bread crumbs instead of panko. I did not have panko in the house. It tasted awesome!
Blair
Thank you, Brenda! That makes me so happy to hear. 🙂