Zucchini and Spinach Gratin

Side DishFrenchGluten-FreeZucchini

Grated zucchini and chopped blanched spinach, mixed with onions sautéed with bacon, parsley, and garlic, bound with eggs, topped with grated Parmesan, and baked.

Photography Credit: Elise Bauer

Another week, another refrigerator drawer filled to the brim with garden zucchini. Sound familiar?

To take a break from our usual (almost daily in the summer) way to cook up the zucchini (see mom’s summer squash), we prepared a classic French gratin, with grated zucchini, spinach, onions sautéed with bacon, a persillade of parsley and garlic, all bound together with a few eggs, tossed with Parmesan, and baked until golden brown.

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Zucchini has never tasted so good!

I think the bacon might have something to do with it.

And maybe the Parmesan. And the onions, and garlic.

Okay, everything. The combination is perfect.

Zucchini Spinach Gratin

The recipe looks more involved than it is. Most of the time is in the baking or in the allowing the zucchini and spinach to drain excess moisture.

The hardest part is grating the zucchini (a breeze if you have a food processor) and the Parmesan. The trick to a successful recipe is squeezing out as much moisture as you can from the zucchini and spinach. Tossing the zucchini with salt and allowing it to drain for half an hour will help draw out a lot of its moisture.

If you don’t do this I’m guessing that you might end up with something that is too loose, with too much moisture for the eggs to do their work as a binder.

Best part? The recipe uses two whole pounds of zucchini! Which in our case should use up at least a day or a day and a half’s worth of garden produce. Enjoy. ;-)

Zucchini and Spinach Gratin Recipe

  • Prep time: 40 minutes
  • Cook time: 1 hour
  • Yield: Serves 4 to 6

The recipe calls for bacon and I think it's an important flavor component. For those of you who don't eat pork, or meat, you can substitute butter and or olive oil (a couple tablespoons) to sauté the onions.


  • 2 pounds zucchini
  • Kosher salt
  • 1 pound frozen spinach*
  • 3 slices of thick cut bacon (about 3 ounces), cut crosswise 1/4-inch pieces
  • 1 large onion
  • 1 handful of parsley (about 1/2 cup of leaves, lightly packed)
  • 3 cloves garlic, peeled, coarsely chopped
  • 1/2 cup freshly grated Parmesan cheese
  • Freshly ground black pepper
  • 3 eggs
  • Extra virgin olive oil

* Or 6 packed cups of fresh chopped spinach leaves, blanched and drained


1 Grate and drain zucchini: Grate the zucchini. Toss the grated zucchini with about a teaspoon of Kosher salt. Place the grated zucchini in a large sieve (or colander) placed over a bowl to catch the water as the salt helps the zucchini release its moisture.

Let sit for 30 minutes or so, then squeeze out the remaining excess moisture with paper towels or a clean tea towel.

2 Thaw and squeeze the spinach: Thaw the spinach, let drain while the zucchini is draining. Then squeeze out the excess moisture with paper towels or a tea towel.

3 Cook the bacon: Heat a large skillet on medium heat. Add the bacon and gently cook until lightly browned and most of the fat rendered out, about 10 minutes.

4 Add onions: While the bacon is cooking, peel and finely chop the onion. Add the onions to the bacon and cook for an additional 10 minutes, until the onions have softened.

5 Prepare parsley and garlic (persillade): While the bacon and onions are cooking, prepare the parsley and garlic. Place the parsley and garlic with a small pinch of salt into a food processor and pulse just a couple of times.

pulse parsley and garlic in a food processor

6 Preheat the oven to 350°F.

7 Prepare the filling: Place the zucchini into a large bowl. With a wooden spoon, mix in the cooked onions and bacon. Mix in the spinach, parsley, and garlic. Mix in half of the Parmesan. Taste, and add black pepper and more salt to taste. Mix in the eggs.

filling for spinach zucchini gratin

8 Fill gratin pan: Coat the bottom and sides of a 2 quart casserole or gratin dish with a tablespoon of olive oil. Put the zucchini spinach mixture into the dish and pack it down. Sprinkle the remaining Parmesan cheese over the top and drizzle with a little olive oil.

zucchini spinach gratin about to be cooked

9 Bake: Bake in a 350°F oven for 40-45 minutes, until the top is nicely browned. Serve immediately. Reheats well.

zucchini spinach gratin right out of the oven

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Inspired by a gratin recipe in Provence: the Beautiful Cookbook.


Zucchini and chard gratin - from Local Kitchen Blog

Elise Bauer

Elise Bauer is the founder of Simply Recipes. Elise launched Simply Recipes in 2003 as a way to keep track of her family's recipes, and along the way grew it into one of the most popular cooking websites in the world. Elise is dedicated to helping home cooks be successful in the kitchen. Elise is a graduate of Stanford University, and lives in Sacramento, California.

More from Elise

34 Comments / Reviews

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Did you make it? Rate it!

  1. Lisa

    Tastes lovely, easy to make, and healthy


  2. pyrlgyrl

    A-maze-Ing! I really wasn’t sure how I would feel about this but it had all the things I love in it so I thought I would give it a whirl I had a huge bag of spinach and kids don’t like sautéed spinach. This is my go to side dish from now on. It doesn’t look like much but wow!



    Since first trying this recipe, I make it all the time. Veggie licious, low carb, everything I want in a dish. Thank you so much!


  4. Kathy J

    Wonderful recipe! Sunday breakfast this morning, the whole family enjoyed it. The only things I would change are cooking the garlic and adding some cheddar on top. Very yummy, would work as an appetizer also.


  5. Sonali

    I tried it today without the bacon, but caramelised the onions a bit with sugar. It was fantastic!

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