Zucchini Gratin is pure summer comfort in under 30 minutes. Thinly sliced zucchini sauté briefly, then baked until bubbly and golden under a Parmesan-breadcrumb crust. It's light without being skimpy-no heavy eggs or cream-and perfect for pairing with grilled meats or enjoying as a warm, veggie-first side any night of the week.
While gardens and markets are overflowing with beautiful summer squash, this zucchini gratin is my favorite way to enjoy it-simple, fresh, and never heavy. Instead of burying the vegetables in cream, mayonnaise, or mounds of cheese, I keep it light so the zucchini flavor shines, finishing with just enough Parmesan and crisp gluten-free breadcrumbs for a satisfying crunch.
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Why You'll Love Zucchini Gratin
- Great for all of that summer zucchini.
- Easy and quick recipe.
- Nice summer side dish.
Here's another easy summer zucchini casserole with tomatoes and herbs.
What You'll Need
- Oil: I prefer olive oil but a neutral healthy oil or avocado oil is good too.
- Zucchini: Green zucchini is what I used the first time but you can mix yellow and green for more color.
- Shallot: Petite member of the onion family with a lovely flavor, and a classic in French cooking.
- Garlic: For that marvelous pungent flavor. Fresh is best, but the tube puree is good too (just read the label for additives).
- Fresh herbs: Fresh parsley and fresh thyme leaves make a terrific combo.
- Breadcrumbs: Either homemade toasted breadcrumbs or store-bought, and gluten -free if needed.
- Parmesan: For a nice crisp, crunchy, crust.
Please see the recipe card for measurements.
Substitutions and Variations
- Swap dried thyme for fresh if fresh is not available. Use ⅓ the amount.
- Swap Pecorino Romano or Piave for the Parmesan cheese.
If you eat wheat, panko crumbs are a good substitution for regular toasted breadcrumbs. - Substitute chopped onion for the shallot.
For another summery side with zucchini, try this Mexican squash with the nice addition of corn. For a main dish zucchini recipe try this cheesy stuffed zucchini recipe called Zucchini Involtini.
Recipe Instructions
Trim off the ends, then cut zucchini in half lengthwise. Cut the halves into thin half moons about. Cook the zucchini quickly in a hot pan with olive oil for just a few minutes until it is starting to brown a bit at the edges.
Turn the heat down, add shallot and cook a minute or two, then add the garlic and cook for 30 seconds more. Stir in fresh herbs.
Pour zucchini into a shallow casserole baking dish that is broiler-safe. The one I use is an 8″x12″ oval baking dish and about 2 quarts. The key is to choose a shallow baking dish, no matter what shape, so everyone gets a good serving of the crunchy topping.
Lightly oil the dish so nothing sticks. Pour in the zucchini, top with a combination of gluten-free (or wheat) breadcrumbs and Parmesan. Pop under a hot broiler for a minute or two until golden and enjoy!
Serving Suggestions
Serve alongside of grilled meats in summertime or easy baked chicken breasts. Zucchini casserole is bets enjoyed the day of cooking as it will soften up (but it still taste good).
Looking for more zucchini recipes? Try this terrific zucchini muffins. Light, tender muffins great for breakfast or a snack.
Recipe FAQs
It depends on the ingredients. Some recipes that are heavy with eggs and cheese may take up to 45 minutes in the oven. Rather than baking, this recipe starts with a quick saute and finishes under the broiler for a crispy top crust. Faster and easier.
Yes, here is how you make a zucchini casserole without eggs. Chop zucchini into bite-sized pieces, saute until crisp-tender and add a little chopped shallot, pour into an oiled shallow casserole and top with a parmesan crumb topping, then broil until browned and crisp. No eggs needed! It's lighter, easier zucchini casserole.
Variations on a zucchini casserole include adding different types of cheese, incorporating other vegetables like tomatoes or bell peppers, using different herbs and spices, or adding a protein such as cooked chicken, ground beef, or sausage.
More Summertime Side Dish Recipes
Looking for more super summer side dish recipes? Try these or take a look at this link for more summertime recipe ideas.
⭐️Did you Make This?
If you make this zucchini casserole, please comment and let me know, and if you loved it, please give it a 5 star rating. They really help other readers. Any questions? Just ask. I'm here to help.
📖 Recipe
Easy Zucchini Gratin with Parmesan Crust
Equipment
- Shallow, broiler-safe casserole dish 1 - ½ quart size
Ingredients
- 2 tablespoons olive oil divided use
- 2 pounds zucchini 7-8 small
- 1 large shallot finely chopped
- 2 large garlic cloves finely chopped
- 2 tablespoons freshly chopped parsley
- 1 tablespoon freshly chopped thyme leaves or 1 teaspoon dried
- ⅓ cup grated Parmesan cheese
- ¼ cup toasted breadcrumbs gluten-free or whole wheat
- ¼ teaspoon Sea salt
- ¼ teaspoon ground black pepper
Instructions
Set up the Broiler
- Adjust oven rack to the medium level or one level up and pre-heat the broiler. Lightly oil a shallow 2 quart, broiler safe baking dish with a little of the olive oil.
Make topping
- Combine breadcrumbs and Parmesan along with 1 tablespoon of olive oil in a small bowl and stir together until well blended.
Trim Zucchini
- Trim ends from zucchini and quarter them lengthwise. Lay the quarters flat and holding your knife level with the cutting board, trim out the seeds, spongy center. If zucchini are small there maybe more be much, if they are large, there will be more.
Cook Zucchini and Shallots
- Heat the other 1 tablespoon of olive oil in a large 12" saute pan over medium heat. Add zucchini to the pan and cook until it is softened and starting to brown at the edges but do not let it get too soft, stirring and turning frequently, about 5 minutes. Sprinkle in the shallot and cook 1 minute. Add garlic and cook 30 seconds. Stir in herbs.
Bake Casserole
- Pour zucchini into the oiled or buttered baking dish and spread the crumb topping evenly over top. Broil until casserole has a golden crunchy top. Serve hot.
Notes
- Swap dried thyme for fresh if fresh is not available. Use ⅓ the amount.
- Swap Pecorino Romano or Piave for the Parmesan cheese.
Nutrition
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Kate S says
Easy and delicious!
Sally Cameron says
Thanks for commenting Kate! Glad you enjoyed it!
Lois says
Fabulous! Nothing more can describe it if you are zucchini lover and even if you are not!
Mrs. O says
The recipe says, “1 1/2 tablespoons olive oil divided use”. I only see the olive oil being used to fry the zucchini. Did I miss a step?
Sally Cameron says
Hi Mrs. O. You mix part of the olive oil with the topping, then use the rest to cook the zucchini. I checked the recipe and it's there in the description, but I did clarify it a bit. Hope that helps! Thanks for the question and hope you enjoy this. I think I'll make it tonight! I also foxed a photo, so thanks again.
Kristen says
Thank you for sharing this recipe - I made it over the weekend and it was fantastic! FYI - After dinner we had half the casserole left over, and with no room in the fridge I decided to experiment. I blended the remaining portion in a food processer and mixed with a little sour cream / greek yogurt.... let me tell ya it makes one HECK of an amazing dip. Like, reeeally good.
Sally says
Thanks for shring that tip Kristen! Sounds fantastic. I'd never have thought of turning leftovers into a dip! Glad it worked so well for you!Very creative!
Mary@SiftingFocus says
Sally, I'm always looking for new and delicious twists on preparing zucchini. Love the healthy and simple approach you took in this recipe.
Madonna/aka/Ms. Lemon says
Our family calls zucchini our new potato. This looks delish.