This Parmesan Squash Casserole is a terrific dish for a potluck or anytime! Everyone loves it.

Doesn't this slice of Momma Betty's Parmesan Squash Casserole look amazing?
Momma Betty's Parmesan Squash Casserole is the best!
Don't you wonder what to do with all that squash in the summer? All of a sudden, you have tons of it. Well, Momma Betty's Parmesan Squash Casserole is one of the best casseroles to help you use it up. It's a super good vegetarian casserole. I make it gluten free and use Pecorino Romano (sheep's cheese), which has a different protein than cow's milk so I'm not allergic to it. The casserole flavor is outstanding, a little Italian seasoning and parmesan or pecorino romano cheese, onions and summer squash. Delish!

Yellow summer squash (or green zucchini) are best for this casserole.
I found this recipe in my mother-in-law's "La Casserole" book of hand-written recipes. Don's mom, we call her Momma Betty, had about 10 or 12 "squash casseroles" in her various clipping and recipe files. Of all of them, this is our absolute favorite. We loved it when she made it for us, and everyone we share it with always raves about it.
Which Recipe Is It?
The problem with the recipe for us was: exactly which squash casserole was the one we liked? So now we know. It's this one! We love it. I hope you do, too.

Momma Betty's Parmesan Squash Casserole
Simple ingredients, takes just a few minutes to prepare and sauté the onions and squash, and then all you need is a beautiful casserole dish (affiliate link). Bake 40 minutes.
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I do! If I eat gluten or cow's milk (in most forms), my inflammation and digestive issues return. I'm so glad I healed myself with food. You might be interested in my story. And my new book, It Ain't Just The Diet Journal, might help you improve your health like it did mine.
What You Need
You will need measuring cups and spoons, knife, cutting board, sauté pan, and a casserole dish. Get the best kitchen tools you can afford. You want them to last a lifetime.
Momma Betty's Parmesan Squash Casserole Recipe

Momma Betty's Parmesan Squash Casserole
Ingredients
- 1½ pounds fresh yellow squash for a single recipe: about 4-6 small squash; you can also use zucchini or a mixture of the two
- ½ cup chopped onion
- 1 tablespoon olive oil
- 1 cup shredded Parmesan or Pecorino Romano cheese for "dairy" free; it is sheep's cheese and had a different protein
- 1 cup mayonnaise
- 2 eggs
- ¼ teaspoon pepper
- ⅛ teaspoon salt
- 2 Tablespoons butter can substitute olive oil
- ¾ cup Italian bread crumbs or ¾ cup cornflake crumbs and ½ teaspoon Italian Seasoning I use gluten free panko crumbs for gluten free.
Instructions
- Sauté the onion and squash in a little olive oil until the onions are translucent.
- Drain well.
- Combine squash with mayonnaise, cheese, eggs, salt and pepper.
- Pour into a greased casserole dish.
- Melt butter and mix with bread crumbs (or cornflake crumbs, for gluten-free) until crumbly.
- Sprinkle on top of casserole.
- Bake 30-40 minutes at 350 degrees or until the custard sets.
Nutrition
Recipe Nutrition Information
This recipe is GF, NF, SF, CF, V*
The information shown is an estimate provided by an online nutrition calculator. It should not be considered a substitute for a professional nutritionist's advice.

Momma Betty's Squash Casserole Nutrition Label (8 Servings)
Nourish Your Body & Soul
I encourage you to care of yourself by eating satisfying, nourishing food that is good for your body and makes you feel healthy. Protect your spirit by living authentically, moving your body, and taking time to replenish and rest. I think you might also like these recipes & posts from Recipe Idea Shop:
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My MIL had about a dozen Squash Casseroles in her "Casseroles" box. And this is the BEST one. Made with yellow squash or zucchini, it's SUPER.
*Allergen Key
GF = Gluten free | DF = Dairy free | NF = Nut free | SF = Soy free | EF = Egg free | CF = Corn free | V = Vegetarian | VG = Vegan
Note: If you have serious allergies or sensitivities, to be considered free of these allergens, you need to use products specifically marked "gluten free," etc. There can be cross-contamination in facilities.
This post was first published on Recipe Idea Shop September 16, 2018 and updated June 29, 2021.
Last Updated on May 24, 2022 by Adriana
Elizabeth Cottrell
This is delicious! What a great way to use up that extra squash.
Don Crawford
I'm glad you enjoy it! We have quite a bit of zucchini. I think I'll make a Squash Casserole this week (even though it's super hot outside).
Mary Fay
Momma Betty’s Parmesan Squash recipe is delicious. The Italian breadcrumbs really add to the flavor of the dish. I think of summer when I cut up the lovely summer squash for this dish. 🤔💭
Lois
Thanks, Mary. I'm so glad you like it. It's comfort food at our house!