Crispy Zucchini Casserole

Summer side dishes don't get better than this zucchini casserole recipe! A crispy, nutty panko topping covers a saucy layer of pesto and zucchini.

Zucchini Casserole Recipe

If you have a mountain of zucchini or yellow squash in your fridge, this zucchini casserole recipe is just the thing for you! In fact, you should try this recipe even if you don’t have any summer squash on hand. The crispy, nutty Parmesan and panko topping contrasts perfectly with the saucy zucchini, pesto, and marinara underneath. It’s super simple to put together, and it can pass as a side dish or a meal on its own. Make this zucchini casserole recipe once, and you’ll have it on repeat all summer long.

Sliced zucchini

Zucchini Casserole Recipe Ingredients

Here’s what you’ll need to make this delicious zucchini casserole recipe:

  • Fresh zucchini, of course! I actually like to use a mix of yellow squash and zucchini in this recipe, but just one or the other would work fine too.
  • Yellow onion – It gives the veggies a savory depth of flavor.
  • Basil pesto – I toss it with the zucchini and onion for richness and fresh, nutty flavor.
  • Marinara sauce – Tomatoes+basil are a match made in heaven, so I couldn’t resist adding tomato sauce to this dish! It helps make the middle of the casserole saucy and bubbly as it bakes.
  • Panko bread crumbs and Parmesan cheese – Together, they create a crispy, savory topping for the saucy squash and onions. I like to turn the broiler on for the last few minutes of baking to get them brown and crisp!

Toss the zucchini slices and onions with the pesto, and cover the bottom of a casserole dish with the tomato sauce. Pile in the veggies, and smooth them into an even layer. Sprinkle the panko bread crumbs and Parmesan cheese on top, and add a pinch of red pepper flakes and a drizzle of olive oil. Bake at 375 for about 25 minutes, until the topping is golden brown and the squash is tender. Enjoy!

Find the complete recipe with measurements below.

Zucchini and summer squash with pesto

Squash Casserole Recipe Tips

  • Slice the zucchini as evenly as possible. The more evenly you slice the zucchini, the more evenly it will bake. You don’t want thin slices to become mushy before thicker ones cook through! I recommend using a mandoline to make sure that your slices are all the same width.
  • Pat the zucchini dry. Zucchini can release a lot of water as it cooks! In order to keep your zucchini casserole from becoming watery, pat the zucchini dry before you toss it with the pesto. Better yet, set the sliced zucchini on a kitchen towel to drain while you prep the other ingredients.
  • Smaller squash = better squash. This cheesy zucchini casserole comes out best when it’s made with small, firm summer squash. Large zucchini have a tendency to be seedy and watery, so I don’t recommend using them here.
  • Make it vegan. This zucchini casserole is a great recipe to make vegan. Replace the traditional pesto with vegan pesto, and use my vegan Parmesan in the topping. Trust me, you won’t miss the cheese one bit!

Summer squash in a baking dish

Zucchini Casserole Serving Suggestions

This zucchini and squash casserole is a perfect side dish for 3-4 people. Serve it with your favorite protein, homemade pizza, or a simple pasta dish. I especially love it with these summer pasta recipes:

For more pasta recipes, check out this post!

Alternatively, make this zucchini casserole a meal on its own. Pile it on a bed of creamy polenta, cooked quinoa, or couscous, and add a handful of roasted chickpeas for a delicious, healthy dinner.

Zucchini and Squash Casserole

More Favorite Zucchini Recipes

If you love this zucchini casserole, try one of these zucchini recipes next:

5.0 from 15 reviews

Crispy Zucchini Casserole

Prep time
Cook time
Total time
This zucchini casserole is the BEST summer side dish! To make this recipe vegan, replace the cheese with vegan Parmesan, and use vegan pesto instead of regular.
Recipe type: Vegetable
Serves: 3 to 4 as a side
  • 4 cups mixed zucchini and yellow squash, thinly sliced
  • ½ cup thinly sliced yellow onion
  • ½ cup basil pesto
  • ½ cup marinara sauce
  • ⅓ cup panko bread crumbs
  • ¼ cup grated Parmesan cheese
  • Pinch of red pepper flakes
  • Extra virgin olive oil, for brushing and drizzling
  1. Preheat oven to 375°F and brush the bottom of a 9x12-baking dish with olive oil.
  2. Set the sliced squash on a kitchen towel to drain some of the excess moisture while you prep everything else.
  3. In a large bowl, toss the zucchini and onions with the pesto.
  4. Layer the baking dish with the marinara sauce, followed by the zucchini mixture. Spread the zucchini into one even layer.
  5. Sprinkle the top with the panko, Parmesan, a drizzle of olive oil, and pinches of red pepper flakes. Bake until the zucchini is tender (but not mushy) and the top is crispy and lightly browned - about 25 minutes. I like to turn my broiler on for the last few minutes to help the topping become browned and crisp.
  6. Remove from oven and let it cool 20 minutes before slicing.



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Rate this recipe (after making it):  

  1. Linda from

    Must make this – it looks delicious!

  2. simple recipe with a lot of flavor.
    Love the zucchini series.. Cheers!

  3. Elizabeth from

    I love new ways to use up Zucchini (Australian) as we always have an over abundance in the garden 🙂 Thanks for sharing! Liz x

  4. Serena from

    Yum that looks delicious – what great way to use courgettes. Can’t wait to try it! Gorgeous pictures as always

  5. Meghan from

    This is almost a sort of inverted vegetable lasagna, simplified. I love it!

  6. Nicole B.

    I just had zucchini for the first time a few months back and became obsessed with it. My husband agrees that this really tasty. Pinned for future making!

  7. This looks phenomenal! Simple, delicious, loads of veggies, and pesto – love it!

  8. Bryan from

    I need more understanding friends like you have. Mostly vegan and mostly gluten free would get me uninvited 🙂 Great recipe! Of course, I’m a gluten meat eater.

  9. Ella from

    This sounds wonderful! I love pesto… I don’t think I’d be missing anything by vega-fying it 🙂 per the above comment, I might try with some nutritional yeast! Thanks for sharing!

    • Elise

      I made it with nutritional yeast & it was as good as you’d think! Give it a try! I mixed the nutritional yeast in with the breadcrumbs.

  10. Jessica

    Thanks for posting! I cook for a family of 5 and only one of us is Vegan, so when it comes to finding family-friendly vegan recipes I love your site! This is reminiscent of pizza for my brothers and they love it 🙂
    I replaced the cheese with some nutritional yeast instead, but I also wanted to try it with some cashew cheese too!

    • jeanine

      so glad you liked it! I love nutritional yeast, I’ll have to try that next time, thanks for the tip!

  11. I have zucchini coming out of my ears! I’m making this tonight, it looks great. Zucchini brownies for dessert too I guess (recipe on my site)!

    • jeanine

      mmm, sounds delish – love chocolate and zucchini together!

  12. Elyse from

    So simple and delcious! I have an abundance of courgettes (sorry just cant bring myself to call them zucchini yet!) Will certainly be trying this, thank you.

    • jeanine

      it’s ok, courgette is so much prettier 🙂

  13. Eileen from

    What a great way to eat up some of the massive late summer zucchini extravaganza! I love it. 🙂

  14. Bring on the zucchini! I love the crispy and baked parts of this, forces me to stray from my usual cutting and roasting!

A food blog with fresh, zesty recipes.
Photograph of Jeanine Donofrio and Jack Mathews in their kitchen

Hello, we're Jeanine and Jack.

We love to eat, travel, cook, and eat some more! We create & photograph vegetarian recipes from our home in Chicago, while our shiba pups eat the kale stems that fall on the kitchen floor.