Zucchini, Eggplant, Tomato Gratin

We're topping this gratin with provolone and Parmesan cheeses. You could easily top it with Gruyere instead. For a more Provencal approach, skip the cheese all together and top with bread crumbs, minced garlic, parsley, and olive oil.

  • Prep time: 20 minutes
  • Cook time: 1 hour, 10 minutes
  • Yield: Serves 6 to 8


  • 3 tablespoons extra virgin olive oil
  • 2 cups sliced yellow onion (1 large onion)
  • 1 cup of sliced red, orange, or yellow bell peppers
  • 1 long eggplant (a slender eggplant like a Japanese eggplant, not a large globe, about 1/2 pound)
  • 1 large zucchini (about 10 to 12 inches long, 1 1/2 inch diameter, about 1/2 pound), or other summer squash
  • 2 medium sized tomatoes
  • 3 cloves of garlic, peeled and smashed
  • 1 1/2 teaspoons salt
  • 2 tablespoons chopped fresh parsley
  • 2 ounces Provolone cheese, sliced or grated
  • 3 tablespoons grated Parmesan cheese


1 Sauté the onions and peppers: In a large sauté pan heat 2 Tbsp of the olive oil on medium high heat. Add the sliced onions and cook until lightly browned, stirring frequently, about 10 minutes.

Add the sliced bell peppers and continue to cook with the onions until the bell peppers are softened and the onions are well browned, about 5 to 6 minutes more.

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When done, transfer the onions and bell peppers into a large gratin pan or casserole dish.

2 Slice the eggplant, zucchini, and tomato in similar sized rounds: While the onions and peppers are cooking, slice the eggplant and zucchini in 1/4-inch thick round slices.

You'll also want to slice the tomato into 1/4-inch thick slices, but depending on how big your tomato is, you may need to cut the tomato in half or in quarters first.

All of the sliced vegetable pieces should be about the same size to make it easier to layer them in an attractive manner.

3 Layer the eggplant, zucchini, tomato rounds on top of the onions, bell peppers as garlic: Preheat the oven to 350°F (175°C). Spread the cooked onions and bell peppers in an even layer at the bottom of the gratin dish. Place the mashed garlic on top of the onions and peppers.

Arrange the slices of the eggplant, zucchini, and tomato on top of the cooked onions and peppers, alternating the vegetables, in an attractive pattern, stacking them and fanning them across the surface of the dish.

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4 Top with salt, parsley, cheeses, olive oil: Sprinkle with salt and parsley. Top with Provolone and Parmesan cheeses.

Drizzle the remaining tablespoon of olive oil around the perimeter, where the vegetables meet the side of the dish.


5 Cover with foil and bake, broil uncovered to finish: Cover with foil (it helps to grease the underside of the foil with a little olive oil so that the cheese as it melts does not stick to the foil).

Bake for 40 minutes at 350°F (175°C). Remove the foil. Turn on the broiler and broil for 5 minutes or until nicely browned.

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  • HausZwei

    I made a less fussy but even better version. I wanted those yummy sautéed onions & peppers mixed in so I cut the Zucs and Eggplant in half moons, used fired roasted tomatoes from a can, mixed that up with garlic and then followed the recipe. Yum! I did make the recipe above and it’s was gorgeous and delicious, but my version is for a weeknight


  • Michelle

    I have a lid to the cast iron pan I plan to use. Can I use it instead of foil?

    • Carrie Havranek

      Hi Michelle! Sure, I don’t see why not. It wasn’t tested using a lid, so I’d just keep an eye on it to see how quickly it is cooking. Thanks for your question!

  • Rita

    I made this, using canned organic diced tomatoes and it was DELICIOUS!!!!!


  • Sarah

    I can’t wait to try this for dinner one night. I’ve been looking for a new vegetable dish to try, and I think this is the one! Thanks!

  • ana

    Absolutely delicious, light and flavorful. Make it at home once a month at least. That is how much my family and I enjoy it. Bake it without the cheese or after taking it out of the oven just sprinkle some good quality grated Parmesan. No need for meat on the side, just some garlic crostini. So much flavor in such a simple dish. Thank you for this amazing recipe!


  • Ria

    Love this dish, I have made it a few times now and I think I’m a bit addicted… have used whatever cheeses I happen to have in the fridge, goats cheese and feta both work well. Such a healthy and satisfyingly tasty dish thanks for sharing.


  • Cathy

    This looks so delicious and I am going to try it but I’m wondering if it will come out watery. Is it necessary to salt the eggplant and zucchini to release some of the water and then rinse?
    I haven’t read any reviews mentioning this being a problem.

    • Summer Miller

      Hi, Cathy! We haven’t had a problem with the dish being watery. Any juices left in the bottom of the pan could be saved and used to make a pan sauce, add to soup or season poaching liquid for chicken or fish!

    • Elise Bauer

      Hi Cathy, the uncovered broiling at the end helps evaporate any excess moisture.

  • isabella

    The dish came out beautiful! The provolone added a nice taste to the vegetables as well! Loved this dish, will make again. Nutritious and delicious!


  • Bianca

    This is such a flavoursome dish! Made it as a side to steak. Lovely, easy and healthy. Will definitely make it again ! Thanks for a lovely recipe x


  • Renee

    Very good! I omitted the peppers because I didn’t have any. I also used green tomatoes from the garden. I added some extra salt and pepper and it was very good!!!!


  • Star

    Fabulous! Great recipe. Great way to use this morning s harvest. Parsley was low so I substituted basil. Everything else the same.


  • Brenda

    Literally just finished making this and loved it. I only had grated Parmesan and goat cheese that I crumbled on top and loved the goat cheese. Had some leftover cooked herbed-crumbled turkey meat and added with green peppers and put on half the dish. Changed the flavour but still very good. It didn’t take that long and I will make this again.


  • Meagan

    This looked beautiful and tasted amazing!


  • christina

    What would happen if I skipped the onion and pepper part below? does it add something to the top zucchini, eggplant, tomato layer? I ask because my bf hates peppers and onions. I love them but maybe I should skip if it is very strong in flavor.

    • Elise Bauer

      Hi Christina, why don’t you just put them under half of the dish? I love them and think they really add to the recipe. Of course you can skip them if you want.

      • christina

        I suppose I can do that. Thanks!

  • Renee McGowan

    At my son’s house sitting with my grandkids, I noticed, too late, that there was no meat thawed out. I found zucchini and eggplant in the fridge, then found your recipe. I used what was at hand. No provolone. No peppers. No oregano. I used parmesan and 3 different cheddar cheeses. Also, I used cauliflower instead of peppers just for volume. As I was putting the cheese on top, it occurred to me that I forgot the tomatoes, which were fire roasted Italian spiced diced tomatoes from a can for lack of fresh tomatoes. So, they went on top. Also, the eggplant I had diced already to make it go further as I am serving it as a main dish. It’s in the oven right now. Photos forthcoming. It smells wonderful in here!!!

  • Joan Jones

    I added a bottom layer of ground turkey mixed with quinoa and it made a delicious main dish. My husband recently had a heart attack and I learned that eggplant is a great food for cleaning arteries. This was the first eggplant recipe I’ve ever tried and we loved it!

    • Elise Bauer

      What a great way to turn the recipe into a main, thanks for the ground turkey suggestion Joan!

    • Natasha

      Hi Joan, how did you cook your ground turkey if you don’t mind me asking? I’d love to make this a main dish!

  • Charles H Rooney Jr

    Do you use smoked Provolone cheese or aged Provolone cheese?

  • FrannyD

    Well this is one delicious dish. I’ve made it several times now with different variations. The zucchini, eggplant and tomato remains the same. Ive sautéed the garlic with the onions and peppers. I’ve doubled it. Changed up the cheese. This time I’ve added feta cheese, fresh basil and parsley. And Italian breadcrumbs mixed with a little olive oil. Panko works great too! Always rave reviews. Great side dish, or a main for the vegetarian .

  • Josie

    Tonight was the second time I made this and it turned out just as delicious as the first time! I used fresh veggies from the garden, plus mixed some bread crumbs, minced fresh basil, thyme and oregano, and shredded Italian cheese mix and sprinkled it over the top before baking. I didn’t use quite as much salt and it was plenty salty. I really like how this cooking method makes the zucchini and eggplant perfectly tender without being soggy or oily. And the dish is really simple! Thanks for the recipe!

  • Barbara Jennings

    I made this and it was delicious. Cutting the vegetables takes a bit of time but so worth the effort. I will make this dish again and again. I’m always looking for good healthy dishes and this is one of the best.

  • Sujata

    Hi Elise. I am happy I stumbled onto your beautiful blog. I love this recipe. I am from India, and was thinking of using some spices with the veggies. At what stage can I use the spices – Spices – crushed dry red chili, minced garlic, minced ginger, cilantro, aniseed, and lemon juice after the dish is cooked. Thanks for your advice.

  • Joan small

    I made the dish
    Followed instruction
    I bought small eggplant
    But still the eggplant was tough
    broil it 5 minutes
    It looked perfect
    WHat did I do wrong

    • Elise Bauer

      You need to bake the dish for 40 minutes and then broil it for 5. If the eggplant is still tough after that, it could be a particularly tough individual eggplant that just needs more cooking.

  • Sandy

    My brother and I made this yesterday for the family ^_^. Followed by sister and I making your Eggplant Parmesean for today’s lunch and both were delicious. I unfortunately could only find the big eggplant so they didn’t cook as fully as the zuchinni or make the dish pretty like yours but everyone still cleaned their plate.

  • Victoria

    I have never cooked eggplant before. When you cut it open do you need to take any seeds or pulp out? Does it need to be peeled?

    • Elise Bauer

      No, you do not need to take out any seeds or pulp. The “pulp” is what you are going to eat. Some thick-skinned eggplants you may want to peel. It depends on the eggplant. For this recipe we are using narrow eggplants with relatively thin skins, so we did not peel them.

  • Lillian

    Leave it to my German oven to complicate this simple recipe. One hour in and the veggies are still crunchy. It looks pretty however.

  • Amanda

    This recipe was able to satisfy 3 meat lovers!!!! I skipped on the parsley and provolone cheese and only added a small amount of parmesan and it still turned out great.

  • shreddie

    I made this tonight on the grill with the lime/cilantro chicken. What a hit! I modified the recipe a bit. I omitted the peppers and I left the onion raw for the bottom layer. I used Roma tomatoes, and I brushed the assembled veggies with olive oil and the crushed garlic. I put everything in a pie tin covered with foil and put it on the grill for about 40 minutes. I added the cheese before serving. There wasn’t any browning under the broiler, but it was still very pretty.


  • Nina D

    Hi, Elise,

    This sounds really good and I actually have everything on hand to make it, but can’t work it into the menu plan until tomorrow night, and we will be out most of the day. Can I get it set up ahead (saute the peppers and onions, lay out the veggies top with the cheese) store it in the fridge and then bake it off tomorrow? I’m wondering if the eggplant, especially, might brown once cut.

    What do you think?

    • Elise Bauer

      Hi Nina,
      Yes the eggplant may brown a little. But I don’t think it will make much of a difference to the taste, and it will be doused in cheese, so it will be hard to see anyway.

      • Nina D

        See? There’s always a good reason to douse anything in cheese! Thanks, Elise.

  • Jan

    Thanks for the recipe. I’ve made it today and it was tasty!
    Coincidentally, on lunch break at work, I was in the restaurant near by and they also served eggplant with cheese (but it was sliced horizontally and baked).

  • Hayley

    I am making this dish tonight for dinner, I do not have a gratin dish, but I have a 2qt casserole dish and a 3 qt casserole dish. I hope those will work in place of the gratin dish! Any advice is welcomed!

  • Walter Underwood

    Oh dear, this was good. I rubbed the leaves off a few sprigs of thyme on top of the onions. And I cooked it uncovered to reduce the flavors a bit. With some bread crumbs on top so it wouldn’t burn. Everyone enjoyed it.

  • Laura

    I love this dish for 2 reasons!!

    1.) I grew all these veggies myself in my garden, eggplant included and they’re all organic veggies!! yay.

    2.) It’s a great excuse to use the mandolin my mom gave me for Christmas (I think it was supposed to be taken as a hint to cook more.)

    Cool, thanks =)

  • Sandy S

    Love the look and ingredients of this recipe Elise! If I can tear myself away from microwaving corn on the cob! I will try it later this week. Looks like it would go good with either fish or chicken… maybe your Grilled Lime Chicken?

  • HappyForks.com

    It looks like late summer on the plate. Classic but still amazing combination of vegetables. If we forget about cheese and we add against them something crispy like nuts or seeds, we have a healthy lunch and no worries about saturated fat and cholesterol

  • Derek the Zen Chef

    You do make it seem so easy; good job of making use of that garden produce! Here in Japan, my zucchini are very fecund, but suffer mightily from mold, since it sib bold hot AND super humid here. I end up with lots of them getting as long as a ballpoint pen no sooner than getting fuzzy and rotten… Ah I recall, you are in drought-stricken California and probably have no such blight, right!
    Parmesan and provolone are my favorites, and I also like how you went easy on the cheese – just a bit goes a long way. Best,

    • Jody K

      Derek, it might also be that they aren’t being pollinated. I lost mine until I started pollinating the female flowers with pollen from the males. I use a paintbrush, it’s the first thing I do each morning. We have a terrifying lack of bees in SE Pennsylvania.

      • Sandy S

        Hi Derek, in addition to what Jody has said, here are few things that might help. One is to only water the ground below the plants. And the 2nd is to keep handy a spray bottle with a solution of baking soda in water (teas./quart or 1 tbsp./gal.) to spray the plants several times a week and always after a rain. In my experience, it is also important to never let the plants go thirsty. That seems to weaken their resistance. And finally, if possible set up a fan to keep a slight breeze on the plants during humid periods.

  • ~Nancy

    I showed this dish to my girls and they freaked out! We have watched Ratatouille countless times and each time we see Remy’s gorgeously beautiful dish made for Ego, we drool in amazement. How can they make an animated dish look so lusciously good? And here you have captured it in real life. I’ll be making this dish, much to the delight of my girls ages 4 & 7. Thanks for your wonderful food blog and all the wonderful dishes I’ve made courtesy of you and your guest bloggers!

    • Jane H

      Nancy, that is so cool and so sweet, and it is the first thing I thought of when saw the picture of the dish! (But I am 52 and neither 4 nor 7, and I sooo love that movie!)