Zucchini, Squash & Corn Casserole – our favorite side dish! Zucchini, Squash, Corn, Onion, garlic, white cheddar cheese, sour cream, mayonnaise, eggs, breadcrumbs and parmesan cheese. Seriously THE BEST!!! Great make ahead side dish. Perfect for all your potlucks, cookouts and holiday meals!
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We are obsessed with this delicious Zucchini, Squash & Corn Casserole. Fresh veggies and cheese are hard to beat! We’ve made this several times over the past month and it has been a hit every time. We really like it with grilled chicken and burgers.
This casserole can be made in advance and refrigerated overnight. I’ve even divided the casserole between two foil pans and frozen one for a quick side later.
This recipe uses “fresh breadcrumbs”. To make fresh breadcrumbs, just pop some bread slices in the food processor and pulse it a few times. I used homemade bread, but any type of bread will work just fine.
This casserole is going to be a staple in our house this spring and summer. This casserole is great for potlucks and cookouts. We are serving it this weekend with our Easter ham!
Zucchini Squash & Corn Casserole
- 1½ lb yellow squash, thinly sliced
- 1½ lb zucchini, thinly sliced
- ¼ cup butter, divided
- 2 cups diced sweet onion
- 2 garlic cloves, minced
- 3 cups corn kernels
- 1½ cups shredded white cheddar cheese
- ½ cup sour cream
- ½ cup mayonnaise
- 2 eggs, lightly beaten
- 2 tsp pepper
- 1 tsp salt
- 1½ cups fresh breadcrumbs, divided
- 1 cup grated parmesan cheese, divided
- Preheat oven to 350ºF. Lightly spray a 9x13x2-inch pan with cooking spray.
- Melt 2 Tbsp of butter in large skillet over medium-high heat. Add zucchini, squash and onion. Sauté for 10 minutes, or until tender.
- Add garlic and cook and additional 2 minutes. Remove from heat.
- Stir together cooked zucchini, squash, onion, corn, white cheddar cheese, sour cream, mayonnaise, eggs, salt and pepper. Stir in ½ cup of breadcrumbs and ½ cup of parmesan cheese.
- Spread mixture into prepared pan.
- Melt remaining 2 Tbsp butter. Combine melted butter, remaining breadcrumbs and parmesan cheese. Sprinkle over casserole.
- Bake uncovered for 45 to 50 minutes.
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Was good and easy enough to to make- simpler than making a rough. Also added some mushrooms and a bit of spinach all had on hand.
I use gluten-free breadcrumbs From a can. I also added two shredded chicken breast. This is what is for dinner. It was delicious. Next time I think I’ll add some jalapeños and mushrooms.
This was excellent. Our squash is coming in fast, so I’m making a batch to freeze. Subbed Fage 0 for the sour cream and didn’t miss it. Added oregano from the garden. This will be a go to recipe from here on out. Great for entertaining, too!
Can I leave out the egg?
Unfortunately, without further recipe testing, I cannot answer with certainty. As always, please use your best judgment regarding substitutions and modifications.
Can this be made casserole be made in a crockpot?
Perfect as is ❤️
This dish never disappoints! I switch it up on occasion making it spicy as a tex-mex side, or emptying out the fridge of left over veggies from previous meals; this casserole is very forgiving! Great entertaining dish that can be made in advance (even the night before) refrigerated, then baked just before company arrives and its still wonderful. Thank you for sharing!
This recipe is awesome. I added shredded parmesan instead of grated parmesan. And used left over helluva good French onion dip instead of sour cream. It gave it more flavor. I also substituted fresh breadcrumbs with stove top stuffing. My family likes lots of seasonings. I used a bag of frozen corn and microwaved it for 4 minutes before adding it to the recipe. I have meat eaters in my home some I added about 1.5 cups of diced ham to the recipe or have used ground sausage in it as well. This recipe is just awesome and you can tweak it so many different ways. Glad I found this recipe
Hi, if using frozen corn, do I need to cook first? Or just throw them in frozen?
throw it in frozen
I used frozen corn too. I microwave it for 4 min first then drain off the fluid before I add it to the mixture. I would think adding it frozen would add more moisture
Made this casserole tonight for first time. We needed another veg to go with Christmas dinner leftovers. My daughter and both commented on how much they enjoyed it. I didn’t realize that I’d left the Mayo out until I read some of the comments asking for subs for it. It was great without the Mayo. Thanks for sharing your great recipe.
How far in advance could I make this? Would two days be too long?
I think 2 days would be fine
my family absolutely LOVED this recipe! I omitted mayo and added a little more sour cream. I also will change out the sour cream and mayo for plain greek yogurt to make it a little healthier in the future. thanks so much!!!!!
I used this recipe and lightened it up some, without totally cutting everything that makes it so tasty. I used a little less butter, used Fage 0% Greek Yogurt instead of the sour cream and most of the mayo (I still used 2 tablespoons mayo), used reduced fat cheese. This recipe makes a big casserole. For seven servings with the adjustments I made, it’s 7 points per serving on the green plan, it would be less on the blue. The servings are huge, and worth every point in my opinion. 🙂
What kind of corn? Fresh, frozen or canned?
Any of the above is fine. I usually use frozen.
This is a keeper! We cook for about a dozen seniors each Friday. They loved it and so did we. We substituted cornbread stuffing for breadcrumbs and topped it with buttered crushed Townhouse crackers.
This casserole is absolutely delicious. I did use store bought bread crumbs and will try with freshly made next time. Still was delicious.
The instruction do not mention (unless I missed them) when to add the corn. Do I add at same time as cheese and mayo?
If I use breadcrumbs from a can, will that alter the recipe much?
It will be fine. Enjoy
What type of corn is being used in this recipe, frozen, canned, cut off the cob?
I used frozen corn kernels
Thoughts on using canned creamed corn?
What a great idea! But unfortunately, without further recipe testing, I cannot answer with certainty. As always, please use your best judgment regarding substitutions and modifications.
Best squash casserole I ever tasted! It's literally a meal in itself. I left out the parmesan b/c I don't like the taste. and used a Ritz cracker topping. The onion gave it a wonderful sweet taste. I wish there were an option to print it. I had to copy it down….not easy considering having to scroll through all those pesky ads!
Lightly salt the slice squash/zucchini on top of paper towels to release excess liquid. Let set about 15 min. Then dab the excess salt/moisture of the top of squash with paper towels.
This is a new favorite for an old lady. Been cooking and baking for over 50 years. Always looking for something new and yummy. I use light mayo and light sour cream and half the butter. Keep the tasty recipes coming. Thx much
Could this be made in a crock pot?
I’m sure it could. You will just have to check on it to see when it is heated through
Do I need to dry the bread out first before putting in food processor? I want to make the fresh breadcrumbs. Thanks ! Doing it later today!
I usually use a day old loaf of French bread. If the bread is super fresh, I might pop it in the oven for a few minutes to dry it out.
What size pan do you recommend? Making it for Thanksgiving and don't want it to run over in my sister's oven ! Lol Thanks
I used a 9×13-inch pan
This was really tasty, but it made a TON of food. If I made this again I would only do a half batch because we just couldn't get through it all. Perfect if you're feeding a crowd.
Made this a few nights ago and I LOVE it! I halved the recipe and it worked out just fine. I might add some ham chunks to make it a one-pan meal, or serve alongside ham. Might also try leaving out the corn and increasing the squash.
Normally I do not eat leftovers (just one of several quirks) but am on my second day of them and finishing it up right now!
Really delicious as is, thank you for posting!!
I'm thinking I would love to add chicken breasts to this and make it a meal. Stay tuned!
Delicious! Won’t cook the veggies as long, maybe 3minutes. My family couldn’t get enough!
This was delicious. I want to make it again but freeze halfWhen you freeze it, how do you cook it? Do you thaw first or place directly in the oven froze? What temp and how long?
We use coconut oil instead of butter and a can of coconut cream instead of the sour cream and mayo and it is so so good and a little healthier!!!!
YUMMY DISH!! LOVE IT!!
Next time I will cook the veggies in 2 batches. It was just too mutch even though I had large pan. I also had lot and lots of liquid after cooking the veggies, I am so glad you mentioned it, I thought I had done something wrong. Perhaps cooking them quicker and at a higher temperature may help!
I have made this delicious casserole four times now and my family loves it so much that the leftovers don’t last more than 24 hours before it is but a memory. I added about 1/2 teaspoon of Grey Poupon which took it over the top! It was just enough tang to cut through all of the creamy lusciousness of this dish. No photos attached because it comes out just like the photo presented here. Make this for your next get together and it will be all people remember!
This was a pretty tasty casserole! It had a slightly weird aftertaste–perhaps the mayo I used. It's a little high in calorie for me to make very often for lunches, since it does have the mayo, sour cream, and breadcrumbs. But, it reheats pretty well, and I didn't get tired of it for a whole week of lunches. Overall I did like it.
After you cook the veggies, there is so much liquid. Do I drain the liquid first?
If you have a lot of excess liquid, I would suggest draining it off.
Looks like fresh herbs were added. I plan to use chives or green onions instead of the sweet onions. Maybe the green is from breadcrumbs? I feel like I'm missing something!! Looking forward to making this tonight!!
Just a little dried parsley to make the photos pretty
about how much squash is 1 1/2 lbs?
I found it was three average size ones.
How much does this make? It looks delicious! I'm on weight watchers, so I like to know how much it makes to figure out how many points per cup/other serving size. Thanks for helping with this!
If you want to freeze it’ do you bake first or freeze first?
I don't bake it first. I just freeze it.
This as delicious! Definitely on my favorite list. We even had a non-veggie eater and he said he would eat it again! Yay!
What else could I replace the mayo with?
Try sour cream or plain yogurt.
Made it this weekend. Delicious!
Any good substitutes for the mayo?
Instead of 1/2 mayo and 1/2 cup sour cream, substitute 1c nonfat cottage cheese
Plain greek yogurt at a 1:1 ratio. Can sub for both mayo and sour cream.
Greek yogurt was what I was thinking – you can add more protein that way.
Do you think white beans could substitute for corn? Although I like the cauliflower idea too.
I, too, would like to serve this with Easter dinner. Guessing you use frozen corn kernels this time of year?
Blending the two types of squash together with the cheese and corn does make a very pretty dish. It also sound delicious and very easy to prepare.
I plan to cut the receipt in half since it is only for two people. 45 minutes seems like a long time to bake it. Should I reduce the time since I’m reducing the quantity? I don’t want it all to be mushy.
Can you make it ahead and bake it later? How much extra time if it was refrigerated?
You can make it ahead. I would add about 15 minutes if you are baking it after being refrigerated
How may squash and zucchini do you use
Doing Keto diet…any good subs for corn or would still be good sans corn & breadcrumbs??
Cauliflower rice for the corn, and crushed pork skins for the bread crumbs !
How much corn?
3 cups corn – and you can also add shredded cooked chicken to make a complete meal cassarole…bob