Easy Zucchini Casserole

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This easy Zucchini Casserole is perfect for bringing to potlucks all summer. Just mix the ingredients, bake, and enjoy!

Zucchini Casserole
Zucchini Casserole

This healthy zucchini casserole has been a hit with zucchini lovers for over a decade. I shared this the first year I started this blog in 2008 and have been making it ever since. The texture resembles a quiche, making it the perfect side dish for brunch, lunch, or dinner. I have dozens of pages full of zucchini recipes that you can check out if you have more zucchinis than you know what to do with. Some of my favorites try are this Zucchini Lasagna, Zucchini Noodles, Zucchini Boats and more!

Zucchini Casserole

How do I substitute Bisquick?

Bisquick Substitute Recipe:

  • 1 cup flour
  • 1 ½ tsp baking powder
  • ½ tsp kosher salt
  • 1 tbsp oil or melted butter

Combine all the ingredients and use it in place of bisquick. Double or triple as needed.

What to Serve with Zucchini Casserole

If you’re hosting brunch, pair the casserole with fresh fruit and turkey breakfast sausage. For dinner, serve it as a side with grilled chicken, fish, or steak and add some roasted potatoes or rice to round out the meal.

How to Reheat Zucchini Casserole

Refrigerate leftover zucchini casserole for up to three days and reheat it in the microwave until warm.

Most Asked Questions:

Below are answers to readers’ most frequently asked questions throughout the years!

Do you peel zucchini before grating it?

You do not need to peel the zucchini before grating it since the skin is so thin.

How do you drain grated zucchini?

Once you have four cups of grated zucchini, squeeze it dry with a dish towel. You can also leave it to sit on the counter between a couple of towels for an hour or two – the moisture will slowly seep out of it. Getting all the liquid out is critical so that the casserole isn’t mushy or watery.

Can I make zucchini casserole in a smaller pan?

I recommend baking this casserole in a 9” x 13” baking pan so it evenly cooks in the middle. If you want thicker casserole slices, you can try baking it in a 9” x 9” pan, but you may need to reduce the oven temperature and increase the baking time.

How do I make gluten-free zucchini casserole?

Use gluten-free Bisquick.

Can you freeze egg yolks?

As a matter of fact, you can! This zucchini casserole recipe calls for three egg whites, and since I hate wasting food, I always try to find a use for the leftover yolks. You can add them to scrambled eggs or omelets or freeze them for later use.

  1. First, add a pinch of salt or about one-third of a teaspoon of sugar (depending on if you’re using them for sweet or savory dishes in the future) so that the egg proteins don’t thicken.
  2. Then freeze the yolks in an ice cube tray and later transfer them to a zip-locked bag or container.


  • Squash: Have a surplus of yellow squash? Substitute it for the zucchini.
  • Seasoning: Add Italian seasoning, garlic or onion powder, or smoky paprika for extra flavor.
  • Herbs: Mix in whatever fresh or dried herbs you have on hand. Basil, rosemary, and thyme would all be delish.

Easy Zucchini Casserole

More Zucchini Recipes You’ll Love:

Zucchini Casserole
Print WW Personal Points
4.40 from 28 votes
Did you make this recipe?

Zucchini Casserole

83 Cals 4 Protein 11 Carbs 3 Fats
Prep Time: 10 mins
Cook Time: 45 mins
Total Time: 55 mins
Yield: 12 servings
COURSE: Dinner, Side Dish
CUISINE: American
This easy Zucchini Casserole is perfect for bringing to potlucks all summer. Just mix the ingredients, bake, and enjoy!


  • 4 cups grated zucchini, squeezed dry with a towel after
  • 1 1/4 cups Heart Smart Bisquick, *see note below to substitute
  • 1/3 cup minced onion
  • 3 large egg whites, beaten
  • 1 large egg, beaten
  • 1 tbsp olive oil
  • 1/4 cup grated Parmesan cheese, good quality
  • 1 tsp kosher salt and fresh black pepper, to taste
  • 1 tsp parsley


  • Preheat oven to 350°F.
  • Mix everything together in a bowl.
  • Spray 9 x 13-inch baking dish with cooking spray and pour mixture.
  • Bake until golden brown and a toothpick inserted in the center comes out clean, approximately 45 to 50 minutes.
  • Cut into 12 equal pieces.


Bisquick Substitute Recipe:
  • 1 1/4 cup all purpose wheat or gluten-free flour mix
  • 1 ½ tsp baking powder
  • ½ tsp kosher salt
  • 1 tbsp oil or melted butter
Combine all the ingredients and use it in place of bisquick.


Serving: 1square, Calories: 83kcal, Carbohydrates: 11g, Protein: 4g, Fat: 3g, Sodium: 253mg, Fiber: 1g, Sugar: 2g
WW Points Plus: 3
Keywords: zucchini casserole, zucchini recipes



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  1. can I use GF bisquick in this recipe?

  2. The casserole was delicious. I changed it a little. The zucchini I used were small ones so I didn’t press the shredded zucchini in a towel. I used 4 eggs instead of the egg whites and one whole egg. I also used regular Bisquick.

  3. I baked this for 30 min and that was plenty of time 
    If I baked it longer it would’ve burned. 
    It was a thick batter and probably would benefit from an 8×8 pan for baking as it spread thin in the 8×13 pan
    Yes I used yellow summer squash 
    Nice flavor

  4. I made this 3 times so far , I made it for a family gathering and everyone loved it so easy to make and delicious 

  5. This was so, so good! It tasted similar to the little ready-frozen petite quiche you can buy. So easy to make, too! Definitely adding it to my regular rotation, especially with my excess of garden zucchini!

  6. My casserole was delicious, not dry or soggy but it did not rise. I used the bisquick. Why did this happen?

  7. How much do you beat the egg whites? Until stiff, forming peaks or just a little? Could you just use whole eggs instead?

  8. Can you make this ahead and freeze it or will it come out watery?

  9. This was delicious and couldn’t have been easier also,  I tried the suggestion about using a salad spinner to remove water from zucchini and that worked great.  

  10. If I make the substitute Bisquik recipe, do I still add the olive oil as well?

  11. Can I use Eggbeaters? If yes, how much?

  12. When you say beaten egg whites do you beat till firm peaks and fold in like you would a cake?

  13. I made this with the suggestion from comments to measure zucchini after its squeezed out. That’s wrong because mine came out pretty dry. Grate 4 cups THEN squeeze it in a towel. I used a gluten free all in one pancake mix but don’t think that was much different than bisquick. Added thyme, parsley, garlic powder and onion powder, could have added more than 1 tsp.

  14. This unfortunately did not work out too well for me.  Im not sure what I could have done wrong.  The recipe is pretty simple and I followed it.  The end result was not what I would call a casserole.  It was flat, like a large, thick, rectangular pancake.  For me it was also too salty (I used one teaspoon salt as directed) though my husband thought the amount of salt was ok.  After baking for 45 minutes it also came out a little dry.  

  15. Hi. Love all your recipes, but this one I had trouble. I used bisquick and sqeezed the zucchini really well but it didn’t really rise at all. Flat and kind of mushy. Any suggestions? I’m going to try again.
    Thank you!

  16. This was pretty good! I made it for dinner as the main dish and I think next time I’ll make this for a brunch. It needed a sauce, I think. 

  17. Can you sub Almond flour in this? I am diabetic and this sounds wonderful but try to keep carbs extra low.

  18. What can be substituted for the bisquick for a low carb dish?  Almond flour? 

  19. This was so good. I used a mix of zucchini and yellow squash. Couldn’t stop eating it right out of the pan. Next time I may use a smaller pan so it’s thicker.

  20. Would this work with yellow squash too? Maybe a combo?