Zucchini Gratin

Zucchini Gratin casserole made with tender sliced zucchini rounds topped with freshly grated cheddar and fontina cheeses and baked to bubbly perfection! This scrumptious seasonal side dish is easy and cheesy!

Zucchini Gratin Recipe

It’s already mid-summer and if I see one more spiralized zucchini recipe I’m going to go berzerk!

I get it; zoodles are fun to say, fun to eat, and they’re trendy as all get out, but they’re are basically assaulting me via Pinterest at this point and I’m contemplating a restraining order. Now do me a favor and slice some zucchini with me?

This easy cheesy zucchini gratin is quite the show stopper and so tasty that we always go back for seconds!

And thirds.

Zucchini Gratin

No fontina? No problem!

You can totally play around with the cheeses for this easy cheesy zucchini gratin!

Gouda and Gruyere are both super melty and full of flavor, so either will pair fabulously with the cheddar. In fact, you could even add all three for a trifecta of meltiness! I won’t tell.

so… how was it?!

Dare I say that I’ve never loved zucchini more?  This zucchini gratin casserole is so flipping good!

I’ve been craving macaroni and cheese a lot lately, but was utterly bored of making it. This? This made me forget all about the noodles!

The zucchini hold their own fabulously contributing great taste and texture accented by the drizzle of creamy sauce and smothering of bubbly cheese. I cannot stand a soggy casserole and rely heavily on blanching to keep my veggies al-dente or within that perfect degree of tenderness.

Oh and the melty fontina-cheddar combo with the kiss of buttery honey cornbread cracker crust? Hold me. Just… hold me!

Ok fine, you can drop me and run into the kitchen to go make this zucchini gratin immediately.

Zucchini Gratin

Zucchini Au Gratin topped with a perfect blend of cheddar and fontina cheeses and baked to bubbly perfection!
5 from 5 votes

Zucchini Gratin

Zucchini Gratin made with tender sliced zucchini rounds topped with freshly grated cheddar and fontina cheeses, baked to bubbly perfection! This scrumptious seasonal side dish is easy and cheesy!

Course Side Dish
Cuisine American
Keyword Zucchini Gratin
Prep Time 20 minutes
Cook Time 20 minutes
Total Time 40 minutes
Servings 4 servings
Author Jenn Laughlin - Peas and Crayons


  • 1 large or extra large zucchini squash
  • 1/2 cup minced yellow onion
  • 1 large clove garlic (minced)
  • 1 tsp extra virgin olive oil (for sautéing)
  • 1/4 cup milk
  • 1/2 cup freshly grated sharp cheddar cheese
  • 1/8 tsp paprika
  • 1/8 tsp garlic powder
  • 1/8 tsp nutmeg (optional but delicious)
  • 1/8 tsp allspice
  • 1/8 tsp salt or to taste
  • 1 large egg
  • 1/2 cup freshly grated fontina cheese
  • 1/4 cup freshly grated sharp cheddar cheese
  • 2-3 TBSP fresh chopped spinach
  • 1/8 tsp red pepper flakes
  • 3-4 buttery crackers, crushed


  1. Pre-heat oven to 350 degrees F and slice your zucchini into discs. No need to break out a mandolin to get them super thin, you'll want them sliced around the same thickness as you'd slice a cucumber for a salad.note: When working with squash as delicate as zucchini, it helps to take an extra step in the cooking process to remove the excess water that pours outta these green gems. The last thing we want to do is eat a mushy, supremely soggy casserole, so my favorite trick is to blanch the zucchini slices and follow it up with an ice bath and a light sprinkle of salt to draw out the moisture tucked away in the squash. It's a small step but made a huge difference in the texture of the casserole. Had I plopped the zucchini in raw, it would have given up all the moisture into the baking dish. The same also goes for overcooked zucchini. So blanch, ice bath, pat dry, and lightly salting is where it's at. Here's how:

  2. Fill a medium bowl with ice water and set aside. Bring a pot of water to boil with enough water to just cover the zucchini discs. Once the water hits a rolling boil, toss in the zucchini slices for one minute, remove with a slotted spoon or drain in a colander, and immediately plunge them into the ice bath to shock the vegetable and halt the cooking process. Next lay them flat on a layer of paper towels, pat the exposed side dry, and sprinkle with about 1/8 tsp of salt, evenly distributed, to draw out the moisture. Let the discs sit while you move on to the onions and cheese!
  3. Grab the now-empty pot you used to blanch your zucchini and bring to medium-high heat with a tsp of olive oil or butter. Saute the onion and garlic until tender and translucent. Add 1/2 cup of grated cheddar along with the milk, chopped spinach, paprika, garlic powder, nutmeg, allspice, and a pinch of salt since you'll be patting some of the salt off the zucchini. Stir well and remove from heat. Stir in your egg and set aside.
  4. Next give your zucchini discs one last paper towel pat to remove any liquid the salt may have drawn out. Line a shallow baking dish [I used a pyrex pie pan] with the sliced zucchini and pour the cheddar-onion mixture over the center. Top with 1/2 cup of fontina and an extra 1/4 cup of cheddar cheese. Sprinkle with a few red pepper flakes, to taste, along with some crushed cracker crumbs. Ritz crackers tend to work great as did the Milton Honey Cornbread crackers I used, anything crumbly and buttery! To keep gluten out of the equation, grab some GF crackers or breadcrumbs or simply skip 'em altogether.
  5. Cover loosely with foil and bake at 350F for around 15-18 minutes until cheese is melted and bubbly. Remove the foil and set the oven to broil on high for an additional 3-5 minutes to give the cheese that extra-golden crust to it, but be sure to keep an eye for it to prevent charring.

Recipe Notes

recipe yields 4 small side dish sized servings or 2 larger sides

Zucchini Gratin

craving more zucchini?

If you get a chance to try this crazy tasty zucchini gratin, let me know! You can leave me a comment here (LOVE checking those daily!) or tag @PEASandCRAYONS on Instagram so I can happy dance over your creations. I can’t wait to see what you whip up!

Zucchini Gratin casserole made with tender sliced zucchini rounds topped with freshly grated cheddar and fontina cheeses and baked to bubbly perfection! This scrumptious seasonal side dish is easy and cheesy! #zucchini #gratin #casserole #vegetarian #sidedish

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  • Kathy

    Have you tried freezing this recipe? Before baking or after?

    • Hey Kathy! I’m not sure how this one would freeze! Have you tried freezing gratin before?

  • Melanie


  • Marjory

    Fantastic recipe! I leave out the crackers to keep it lower in carbs for my hubby.

  • Mary

    I made this today but made a couple of changes to make it dairy free. I used ghee goat cheese and coconut milk. It was AMAZING!!

    • Ahhhh yay! So happy to hear it worked, Mary. Thank you!

  • Rosemary

    I have so many zucchini every summer from the garden and this is one of my favourite ways to cook it. Thanks for a delicious recipe.

    • You’re super welcome! Glad you’re loving the recipe!

  • Mary

    Would almond milk or coconut milk work?

    • I haven’t tested it with either yet but think it’s for sure worth a try Mary! In my Green Bean Casserole Recipe I make a roux with flour, butter, and almond milk and loved the creaminess it gave the casserole. Let me know if you get a chance to experiment!

  • Jane

    Hi, is it possible to replace the crackers with no bread alternative ?

    • Hey Jane! There are a number of swaps you could use and skipping the topping works great too. Are you looking for something gluten-free to use in place or something low-carb/keto?

  • Karen

    I was just wondering what you consider a large zucchini? I have a hard trying to figure that out. Hope you can help.

    • I usually consider squash around 8-10 inches in length to be the big ones! Typically farmer’s markets have really big zucchini and grocery stores carry the smaller ones, which you can still totally use just grab two! 🙂

  • Dena Graham

    The instructions say to add chopped spinach but I don’t see that in the ingredient list. Also, milk is in the ingredient list but I don’t see it used in the instructions. Please clarify because this looks yummy, but I think there are a couple mistakes in the recipe perhaps.

    • Jenn

      Hi Dena! The spinach is in the recipe, I promise! It calls for 2-3 TBSP chopped spinach. Sometimes I add a little, other times I add a lot depending on what we have on hand and what we’re in the mood for! Ohmygosh and thank you for pointing that out about the milk! I added it along with the cheeses after sauteeing the onion/garlic and will update the instructions right away! Much appreciated and I hope you adore the dish as much as my family does! It’s on repeat here this time of year! <3

      • Dena Graham

        Thank you so much for your quick reply. Sorry about overlooking the spinach. I will be trying this right away with zucchini from our garden. Yummy!

        • Jenn

          I’m so excited you’re making it, def keep me posted and let me know what you think Dena! Happy almost-Friday! 🙂

  • Carmen

    This is ridiculously good!!! I could eat it twice a week…at least. Thank you for this awesome zucchini alternative!!

  • Miss Polkadot

    Oh, this would be amazing in a skinny vegan version omitting all the cheese. [dramatic pause] Kidding. Give me all the cheese. I have a feeling this would go over very well with my parents using zucchini from their garden when I’m visiting them at the end of the month.

  • Thankfully I don’t have a spiralizer so I haven’t jumped on the zoodles bandwagon yet, although your bandwagon I’d be happy to jump on.

  • Maria

    I’m sick of zoodles and I haven’t even used my spiralizer yet. The irony.

  • Marnie @ SuperSmartMama

    Thanks for the trick on getting the extra water out of zucchini! I’m going to have to give that a try!!

  • Yummm. We have a couple of zucchini in the fridge that need to be eaten. I think I’ll make this tonight. Who doesn’t love cheese on stuff?

  • Katy

    YUM!!! I have a giant zucchini from last week’s farm share that I need to use. Thanks for the idea!

  • Julie

    I have a dumb colonoscopy tomorrow. Blah. My dad has had polyps for over 40 years, and his only brother died of colon cancer, so it’s a pretty strong family deal. As a result, I have a routine one tomorrow. Stephie wrote me about your deal. I’m emailing you later today.

  • Julie

    Cheese! Cheese! Cheese! I may or may not be addicted to cheese. I actually spiralized my zucchini for the first time the other day. It took freaking for.e.ver. I can slice that baby on my mandolin much quicker. I’ll all over this dish. Well, later. Can’t eat today, so what am I doing? Checking out food blogs. Yeah. I’m intelligent.

  • Liziheartvegetables

    Yum! I’m going to try to ice bath trick for my zucchini lasagna recipe (since sometimes it can get a little soggy!)

  • mm i love zucchini! this dish might change my husband’s mind on the veggie! xo jillian – cornflake dreams

  • I love this idea. My FIL is suffering with a courgette glut (woe) so I’m sending this straight to him!

  • Arman @ thebigmansworld

    I will swap you caramel pecan bars for this. I swear you purposely tailor your recipes to Meg and I…..stop it.

    Just kidding, don’t.

  • I could eat this every night of the week, love it!

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