Incredible Parmesan Zucchini Gratin (Zucchini Casserole)

This website may contain affiliate links and advertising so that we can provide recipes to you. Read my privacy policy.

Cheesey Zucchini Gratin has layers of creamy, cheesy sauce and is topped with a crunchy buttery topping. Ooey-gooey and cheesy, this low-carb take-on comfort food will please any crowd!

This recipe is a twist on classic scalloped potatoes. Gratins are so rich and indulgent, they make any meal a joy to serve and eat. Try creamy cauliflower, brussels sprouts, or potato and mushroom gratins for a more mouthwatering flavor you will LOVE!

Parmesan Zucchini Gratin in a white dish.

Zucchini Casserole Recipe

If you want a side dish to impress this is it! Not only is Zucchini tasty, but it’s also good for you too! It’s low in calories, keto-friendly, and packed with antioxidants, potassium, and vitamins B and C. For those times when you really want comfort food but don’t want to overload in calories, this is the dish for you. Zucchini gratin is just as satisfying and filling as a potato dish with half the carbs!

The other great thing about this recipe is that it is extremely easy to throw together. It utilizes so many simple ingredients that you may not even need to go shop for any! I know your family is going to go crazy over this quick and easy dish. As a side, it pairs so well with a variety of dishes, but honestly, this zucchini gratin is so good, you may want to just eat it alone!

Zucchini Gratin Ingredients

These pantry staples come together to create the most hearty, cheesy goodness! Zucchini gratin is the perfect combination and the best side dish at the table this summertime. For complete recipe details, see the recipe card below.

  • Zucchini: You will need 6 small zucchinis, sliced. You can also grate your zucchini instead for a more noodle-like texture.
  • Mozzarella Cheese: The stretchy, melty texture of Mozzarella is perfect for gratins.
  • Parmesan Cheese: Parmesan adds a great flavor and nuttiness.
  • Cheddar Cheese: Cheddar is always a favorite for sharp flavor and color.
  • Heavy Whipping Cream: Adds moisture and thickness to your creamy sauce.
  • Flour: For use as a thickening agent. All-purpose flour works great!
  • Butter: Adds a rich flavor to your gratin. Everything is better with butter!
  • Salt: Add more or less to taste.
  • Garlic Powder: For a perfect savory flavor! Trust me, you want garlic in this.

Zucchini Gratin Cheesy Topping

If you love cheese then this topping is to die for! Bake the zucchini gratin just enough to have the cheese melt with that crusted overlay on top of the casserole. You are going to love this combination once baked!

  • Bread Crumbs: You can use Panko or Regular bread crumbs
  • Parmesan: This adds extra flavor and texture to your gratin.
  • Butter: Holds everything together and helps it taste amazing.

Making Three Cheese Zucchini Gratin

In just 4 easy steps, you will have a delicious dinner that the whole family will love! This zucchini gratin recipe only takes 15 minutes of prep time and then it’s hands-off!

  1. Mix Together Sauce: In a medium sauce pan melt the butter and whisk in the flour until thick. Slowly whisk in the heavy cream. Stir in the cheese and mix till melted. Add in the garlic powder and salt.
  2. Layer: Cut the zucchini into ¼ inch slices. Layer on the bottom of sprayed 2 quart casserole dish. Spoon some of the sauce on top of the first layer. Layer more zucchini and sauce till you’ve used it all ending with sauce last.
  3. Add Topping: For the topping mix together the bread crumbs and parmesan and sprinkle on top. Pour the melted butter on top.
  4. Bake: Bake at 375 degrees for 25-30 min till bubbly and heated through. Broil the top for about 5 minutes until golden brown.
The process of making zucchini casserole.

Parmesan Zucchini Gratin Tips and Variations

Parmesan zucchini gratin is an easy, tasty dish that everyone will enjoy. Use these great tips and tricks to customize and enhance your dish!

  • Using Different Cheeses: You can definitely mix up the cheeses to your liking or to work with what you’re serving. From cream cheese, feta, to pepper jack you can get creative with it. Gruyere and brie are also great additions- they add more creaminess to your zucchini gratin sauce.
  • Cream: You can use half and half if you want to reduce the fat of your gratin.
  • Cut Zucchini Evenly: Slice your zucchini evenly so that it cooks at the same rate. You can use yellow zucchini here as well or a mixture of both.
  • Spices: Add in different spices for extra zing. Make it Italian with basil and oregano. For a Mexican take, use cumin, chili powder, and paprika.
  • Toppings: For a fun twist, try French fried onions on top! I also recommend sprinkling homemade Italian seasoning on top for an extra pop of flavor.
  • Zucchini Too Watery: Zucchini naturally has a very high water content, so there are a couple tricks I use to make sure your gratin doesn’t become too watery. The first is to sprinkle your freshly cut zucchini with salt and let it sit in a strainer. The salt will work to pull the water out. You can also sauté your zucchini before layering to reduce its moisture.
Parmesan Zucchini Gratin in a white dish.

What to Serve With Zucchini Gratin

Parmesan zucchini gratin pairs perfectly with grilled meats and seafood. Try a roasted chicken or baked salmon for a super satisfying meal. This gratin is so good on its own, though, you could easily have this as your main dish served with a loaf of crusty bread and a side salad and you’ve got a delectable dinner on your hands!

Storing Leftover au Zucchini Gratin

  • In the Refrigerator: Keep in a sealed container for up to 3 days in the fridge.
  • To Reheat: Cook in oven at 350 degrees Fahrenheit until warm.
  • Make Ahead: You can mix this up and freeze for up to 2 months. Thaw overnight in the fridge and then bake as directed. You may need to add 5-10 minutes to make sure it cooks all the way through.
Taking a scoop of Parmesan Zucchini Gratin.

Three Cheese Zucchini Gratin

4.67 from 3 votes
Three Cheese Zucchini Gratin has layers of creamy, cheesy sauce and is topped with a crunchy buttery topping. Ooey-gooey and cheesy, this low-carb take-on comfort food will please any crowd!
Prep Time 15 minutes
Cook Time 25 minutes
Total Time 40 minutes
Author Alyssa Rivers
Servings: 6 Servings


  • 2 Tablespoons butter
  • 2 Tablespoons all-purpose flour
  • 1 teaspoon salt
  • 1/2 teaspoon freshly ground black pepper
  • 2 cup whipping cream can also use half and half
  • 1/2 cup grated Parmesan cheese divided
  • 1 cup shredded mozzarella cheese divided
  • 6 small zucchini sliced about ¼ inch thick
  • Snipped fresh chives for garnish


  • Preheat oven to 400 degrees. Lightly spray a 2-quart casserole dish with cooking spray and set aside. In a small saucepan melt 2 Tablespoons butter over medium heat and which in the flour, salt and pepper. Add the whipping cream and stir for about 2 minutes until it starts to thicken. Add ¼ cup parmesan cheese.
  • Arrange half of the zucchini in the prepared casserole dish overlapping each other. Spread half of the sauce on top followed by ½ cup mozzarella cheese. Repeat with another layer of zucchini and sauce topped with mozzarella cheese and remaining parmesan cheese.
  • Bake for 25 minutes or until the zucchini are fork tender and the top is starting to brown. Sprinkle with chives before serving.


Updated on July 23, 2021
Originally Posted on August 7, 2014


Serves: 6

Calories423kcal (21%)Carbohydrates18g (6%)Protein21g (42%)Fat31g (48%)Saturated Fat19g (95%)Cholesterol93mg (31%)Sodium1103mg (46%)Potassium619mg (18%)Fiber2g (8%)Sugar7g (8%)Vitamin A1369IU (27%)Vitamin C35mg (42%)Calcium560mg (56%)Iron2mg (11%)

All nutritional information is based on third party calculations and is only an estimate. Each recipe and nutritional value will vary depending on the brands you use, measuring methods and portion sizes per household.

Course Side Dish
Cuisine American
Keyword zucchini casserole, zucchini gratin
Tried this recipe?Mention @alyssa_therecipecritic or tag #therecipecritic

Alyssa Rivers

I am Alyssa and the blogger behind The Recipe Critic. I started my blog in June of 2012 as a place to share my passion for cooking. I love trying new things and testing them out with my family.

Read More Posts by Alyssa

facebook twitter pinterest instagram



Leave a reply
  1. 5 stars
    Super tasty!!! Does anyone know how much 6 small zucchini comes out to in weight or otherwise? I made this last night and only had huge zucchini’s and I’m pretty sure I got the ratio way wrong since it was super runny. I don’t think I used enough zucchini and I’m not sure I cooked the sauce long enough. Even being runny, my husband and I still ate it all and I will definitely be making it again (with a couple modifications). 🙂

    1. Sometimes I’ll google an average zucchini size and weight and try to go that way. Also in.tops – you can a) sprinkle zucchini with salt and let it sweat or b) preroast to get some of the water out before you layer it. I think this info is also

    2. 4 stars
      Made it today, it’s cooking now. Smells amazing! I’m curious, description says 3 cheese but recipe only mentions mozzarella & parmesan. I had to double the recipe & so I also added in cheddar. Also, mentions garlic powder but doesn’t say how much or when to add. I substituted the 2 teaspoons of salt for doubling to 1 teaspoon salt & 1 teaspoon of garlic salt & added some garlic powder. The only other change I added was some breadcrumbs on top for a little crunch. I can’t wait to bring it to our picnic, it smells amazing! Thank you! I’ll come back and add review after I’ve tried it.

  2. I’m a bit confused at the 3 cheese mention? I only see 2 in the recipe. Also, you don’t have the bread crumbs amt to use?

  3. Promising recipe, but there are only 2 cheeses in the recipe – what happened to the cheddar cheese mentioned in the preamble?

    1. 5 stars
      Great ingredient swap, especially for me since potatoes just vet in the way! Might as well have zucchini, especially this time of year, so thank you!

  4. I have zucchini coming out of my ears and am ALWAYS looking for a new and unique ways to cook it. This looks amazing! Thank you so much!

  5. That looks amazing. I haven’t been able to convince my kids that zucchini is edible yet. Perhaps the cheese will turn them into believers. I’m in NC too, I’m over the rain too. My house is always dark anyway since we have so many trees, but lately I have to turn on every light in the house to see.

  6. I have never even once thought to do this with zucchini!! OMG! It looks incredible girl. Love 🙂

    PS- I don’t know what the lighting situation in your house is, but I’ve found on the cloudy days here (since we’re in the same place for a week or two longer), if I’m shooting at 1pm on the nose, I can usually get good light.

Leave a Reply

Your email address will not be published.

Recipe Rating