Zucchini Gratin

CATEGORIES: Gardening, Vegetables

Cheesy Zucchini Gratin with Breadcrumb Topping from Our Best BitesPlease don’t hate me.  Yes, I’m posting another zucchini recipe.  And I know there’s no law that says you must consume EVERY vegetable that comes out of a garden, but when you work and plow (okay, fine.  No actual plowing occurred) and sweat over a summer garden and those little seeds grow and finally start producing legit food products, there exists an uncontrollable urge to not let a single one go to waste.  If you’re already sick of my barrage of summer squash, just wait.  A few weeks from now when you’re tired of my tomato recipes, you’ll be begging for more squash.

Here’s the thing.  I posted a bunch of my favorite zucchini recipes last week and one problem a lot of people have with zucchini and squash recipes is that they usually use one or two per recipe.  Which is great- don’t get me wrong.  A few here and a few there and they all get used up, but sometimes don’t you want a recipe that uses a whole crap load of those things?  Here’s the ticket right here.  This recipe uses lots of zucchini or yellow squash, it’s easy to make, you can make a big batch and feed a crowd (hello summer potlucks) and I’m not exaggerating when I say, it’s sooooo so so so so good.  Like, this is honestly maybe my favorite way to eat zucchini yet (well, except for Chocolate Zucchini Bread, but let’s not be silly.  That wins every time and we can’t really compare apples to oranges here.  Or vegetable dishes to chocolate cake.)  This takes thin sliced squash, buttery caramelized onions, a light creamy sauce, and tops it with melted cheese and toasted breadcrumbs.  So seriously, if you’ve got a garden, or a neighbor with a garden, you must make this.  It’s awesomely delicious.

The onions cook the longest, so start with those.  I happen to have a garden full of Walla Walla Sweets, so I grabbed a few of those.

Fresh Garden Onion

Slice those up and toss them in a big (biggest you have, seriously) skillet with some melted butter.

Caramelizing Onions
While those are cooking, stir them every few minutes, but work on prepping the rest of the ingredients.  You can use zucchini or yellow squash, or a combination of both.  I used a little of both.  Slice it into 1/4 inch slices.  If your squash is pretty large, I’d slice it in half lengthwise first.  And if you have a mandoline, this is a great time to use it!  Perfectly even slices every time.

Sliced Zucchini
Those get tossed in the skillet after the onions are tender and starting to caramelize.  It’s important to use a large pan here because we need to get rid of a lot of moisture.  If the zucchini are crowded, they’ll just end up boiling and we want all of that excess water to evaporate so the dish isn’t watery.

After the squash cooks down  we’ll add salt, pepper, a little garlic, and a pinch of nutmeg.  The nutmeg might sound weird, but don’t leave it out!  Don’t worry, it won’t make your veggie dish taste like pumpkin pie.  Nutmeg is a classic flavor component in white sauces and that’s what we’re making here.   It just enhances all of the flavors and makes it taste delicious.

Cooked Sliced Zucchini

Cook that for a few minutes longer (your zucchini should be pretty tender at this point) and then add a spoonful of flour and a little milk (non fat is just fine.)  You get the decadence of “cream” sauce, but with not too many added calories, and with just 1/2 cup of milk going in, it doesn’t drown the veggies; it just gives them a light coating and makes them creamy and flavorful.

Milk into Gratin Sauce
Bring the heat up to get that milk simmering and it should quickly turn into a sauce and thicken.  Now it’s ready to go into a baking dish.  You could easily make it up until this point and keep it in the fridge all day until you’re ready to top it and bake it for dinner.

Zucchini Gratin in panYou’re seeing a tiny dish in my photos.  That’s because I made a half-batch of the recipe in this post just for my husband and I.  Also, I really wanted to use that adorable little polka-dot baking dish.  But you can see how much the vegetables shrink down.

For the topping, combine some Italian flavored bread crumbs and some Gruyere cheese (one of my most favorite cheeses.)  You could sub freshly shredded Parmesan, or another mild white cheese like baby swiss or muenster if you have one of those on hand.

Breadcrumbs and Gruyere
Sprinkle it over the top of your baking dish.  If your food is bursting out over the top of you baking dish like mine is, make sure you put it on a piece of foil, or a large baking pan to catch any drips.  I drizzle just a little bit of olive oil right over the top as well, to help those little bread crumbs toast up nicely.

Pre-Baked Zucchini Bake
Then just bake it in the oven for a few minutes and watch that cheese melt and the breadcrumbs toast to perfection.

Yummy Cheese Topped Zucchini Bake from Our Best Bites

Definitely let it sit for a few minutes before serving to set up (and so you don’t scorch your face off.)

Zucchini and Squash Gratin from Our Best Bites
We ate this along with a great grilled steak hot off the grill and it was the perfect summer meal.  The zucchini gratin was hearty enough that we didn’t need much else.  Perfection.

Cheesy Zucchini Gratin from Our Best Bites





  1. Sigh. We just moved from MN (where I had 30 square feet of garden, which included moe zucchini than I could handle) to Charlotte NC, where my garden barely exists and was started too late anyway for much yield. I’m dying over here- and your awesome recipe is not helping! LOL!

  2. This looks wonderful! Since aged cheeses like Gruyere contribute to my migraines, do you think Mozzarella or Monterey Jack would do? They aren’t aged the same, but certainly don’t have the rich flavor either… Any other suggestions?

  3. Is this watery? I made something like this before and the zucchini had so much liquid after it baked – I had to drain it on a paper towel – haha

    1. Nope, not watery at all. If you were to put raw zucchini in there, I can see how that could be a problem, but saute gets rid of extra moisture and what’s left creates a sauce.

  4. No garden (yet), but I expect zucchini in our CSA box next week 🙂

    Btw, would you gals consider posting a mandoline tutorial? I have one but I am bad at it…

    1. Marnie- what kind of problem do you have with your mandoline? You should be able to just easily slice, slice, slice!

  5. Yum, this sounds incredible! We got about 10 pounds of zucchini out of our garden today. Can’t wait to try this!

  6. I like your pan, I saw your instagram picture. My friend and I went on a mad dash to Tai Pan to get them after your post. I had to go to 2 different stores to get more color options! Sadly, they were all out of the largest pans.

  7. Hi Sara. I’m wondering what size pan to use if I half this recipe? An 8×8? I was thrown off a bit by your small pan. Is your cute orange pan an 8×10?

    1. No, the FULL recipe can be baked in an 8×8. My little tiny one is probably 4×6 inches. You’ll need something really small!

  8. Never too many zucchini recipes!! My garden is doing great and I am always looking for new ways to cook zucchini, eggplant, peppers, butternut squash and tomatoes!! (Hint hint hint)

  9. I have to laugh – on the one hand, this dish sound delicious. I love anything made with zucchini, but ironically, can’t have a garden to produce them. On the other hand – like I said in my own blog recently: Preheat oven to 400 degrees. Seriously? (Don’t you know how hot it is already?)LOL

    1. I think it depends on where you live. It’s hot here, but because of that my AC is pumping and my house is super cold. I sometimes wear a light sweatshirt inside and baking doesn’t phase me!

  10. oh, I have another question… 🙂 I don’t have Italian style bread crumbs. But I do have a lot of Panko bread crumbs. Could I just mix in a few shakes of the McCormick Italian seasoning into the Panko crumbs to get the same affect? Or do you think it would alter the dish too much? Thanks…

  11. Oh, my goodness! That baking dish is ADORABLE!!! Where would one go to get a cute pan like that?!? 😀 The recipe looks delicious–can’t wait to try it with the armfuls of zucchini we picked yesterday.

  12. Just prepped this with my littles this afternoon with veggies they picked from our garden. Waiting to go into the oven in a little bit for dinner. Feel free to keep the zucchini recipes coming!

  13. I added ground beef and made it a main dish. Also subbed parmesan cheese because I had it on hand…AMAZING!! Definitely a keeper in our house!

    1. That’s such a good idea; I was thinking it would be really good with some chopped ham or Italian turkey sausage; I’ll have to try that next time!

  14. I made this for dinner tonight and my husband loved it! Mine turned out a little watery but it still tasted delicious. Thanks for the great recipe!

    1. That’s weird it turned out a little watery, mine wasn’t watery at all. You might have had an extra juicy zucchini or needed to cook the sauce a bit longer. But I’m glad it was delish!

  15. This is delicious! I made a special trip to get the Gruyere, and boy oh boy, and I glad I did! It really made this over the top. Even my zucchini hating son ate it up.
    May I suggest moving the instruction to pre-heat the oven to after the onions are done? My oven was on for almost an hour by the time I was done, and that really heated up the kitchen.

  16. This is so yummy! I love how the nutmeg enhances the zucchini & pepper. My 1 & 4 year old ate it right up! I have made it twice in the past week & plan on making it again tonight. I couldn’t find the cheese but substituted 1/4 cup each of parmeasan & Swiss, added about a 1/4 cup of a colby jack blend that I had on hand & it turned out amazing! Thank you for such a delicious recipe.

  17. There is no such thing as too many ways to use up garden produce, especially when made in a bestbites-worthy fashion. Thank you thank you and keep em comin! Can’t wait to try this one!

  18. I have to be honest, we’re not very creative around our house when it comes to veggies. We mostly do boring stuff like mashed potatoes, corn, green beans…yada, yada, yada. Well, I just have to say thank you, because this recipe surprised me, it was really tasty. It’s given me the confidence to try more vegetable recipes. Wish me luck!:)

  19. Just wondering if you really cook the onion for 20 min. I made this tonight and it turned out wonderfully, but I did not cook the onion for more than 2 or 3 min.

    1. Hi Sylvie- Out of respect for original authors, we always mention if we change the recipe in any way, and I made sure to site Ina as the author. In this particular recipe, I did add garlic, as well as decreased the amount of butter. I also used a different style of bread crumbs and changed the method of using the milk and flour. I’m not trying to take credit for Ina’s wonderful recipe, I’m letting people know that I made it a little differently.

  20. Made this today for lunch and loved it! I added some goat cheese to the sauce because I had some handy. Delicious!

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