Southern Squash Casserole

It’s the kind of side dish that’ll steal the show.

By
Sara Bir
Sara Bir
Sara Bir
Sara is a chef, culinary educator, and author of three cookbooks, The Pocket Pawpaw Cookbook, Tasting Ohio and The Fruit Forager's Companion. The latter won a 2019 IACP Cookbook Award.
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Updated June 13, 2025
Sara Bir
Southern squash casserole in a casserole dish (a serving size already served)

Simply Recipes / Ciara Kehoe

Why Make This

• Southern Squash Casserole features tender cooked yellow squash topped with a buttery cracker crumb topping.
• To make it, steam squash and onion, then mash. Combine the mashed squash with egg, mayonnaise, shredded cheese, salt, and pepper, and scrape into a baking dish. Top with buttered cracker crumbs, then bake.

Rich and comforting, Southern squash casserole is one of those vegetable side dishes that’s not really about the vegetables. Yes, it’s packed with yellow squash cooked until tender. But its appeal lies squarely in its buttery cracker topping. That distinctive yellow squash flavor comes through, but everyone knows all that squash is a supporting player to the golden brown crushed crackers doused in melted butter.   

This easy casserole is a side dish welcome at any potluck, Sunday dinner, or gathering. It’s commonly found as an option at Southern meat-and-three restaurants, but it’s so simple to make at home.

The Ever Adaptable Squash Casserole

Open up any community cookbook published in the 1970s or 1980s and you will likely see multiple versions of squash casserole recipes. Often the cookbooks’ only squash recipes, in fact. This goes for many American community cookbooks, not just Southern ones, but as far as I know, this casserole originated in the South. 

I perused my own treasured cookbook collection and easily found many versions; one cookbook even had three different recipes on the same page! Though so many iterations exist, they’re all essentially cooked summer squash and onions bound with something rich and creamy: any combination of eggs, cheese, mayo, sour cream, canned condensed soup, or all of the above. Plus, the aforementioned crumb topping, which can be breadcrumbs but really should be crackers because, in this instance, they’re just better.

I wanted to keep it simple and streamlined, and in my experiments, mayonnaise plus an egg and some grated cheese delivered the right balance of substance without overwhelming the squash. Plus, most everyone has eggs, mayo, and cheese in the fridge, which allows you to make this casserole on a whim if you have abundant yellow squash.

spoonful of squash casserole lifted from casserole dish using a wooden spoon

Simply Recipes / Ciara Kehoe

How to Keep Squash Casserole from Getting Watery

Squash releases a lot of moisture as it cooks, and you want to drain it away before mixing up the casserole. My easy trick for doing this is to mash the cooked squash in a colander so the excess moisture drips off. No watery casserole!

Variations

  • Yellow squash in this casserole is iconic, but you can use zucchini or other tender summer squash.
  • Cheddar cheese delivers a deep color and good character to the casserole, but any cheese you like works. I actually love it with Velveeta! Mixing Swiss or Parmesan with the cheddar adds even more flavor.
  • I prefer Club or Ritz crackers in this recipe, while my mom says Cheez-It or Goldfish are superior. Even plain old saltines work, though.
  • Yes, you are tossing the cracker crumbs in extra butter, but starting with good buttery crackers in the first place makes a lot of difference. I used Club crackers and off-brand ones in my testing, and the version with the Club crackers easily beat out the one with knockoffs.  
  • If mayo makes you shudder, you can replace the mayonnaise with sour cream, adding a little extra salt.
  • A little fresh or dried thyme adds a nice dimension.

More Casserole Sides

Southern Squash Casserole

Prep Time 8 mins
Cook Time 38 mins
Total Time 46 mins
Servings 8 servings
Yield 1 (8x8-inch) casserole

You can easily double this casserole and bake it in a 9x13-inch dish.

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Ingredients

  • 3 tablespoons unsalted butter

  • 1/2 sleeve Club, Ritz, or Cheez-It crackers (2.5 ounces), crushed (1 cup crumbs)

  • 3 medium yellow squash (about 24 ounces), sliced or cut into roughly 1-inch pieces

  • 1/2 yellow onion, diced

  • 1 large egg

  • 1/3 cup mayonnaise

  • 1 1/2 cups grated cheddar cheese

  • 1/2 teaspoon salt

  • 1/4 teaspoon freshly ground black pepper

Method

  1. Preheat the oven to 350°F. 

    Put the butter in an 8x8-inch or 2-quart casserole dish and pop it in the oven to melt as it preheats.

  2. Toss the crumbs with the butter:

    Once the butter has melted (it usually takes 5 to 8 minutes), add the cracker crumbs to the dish and toss to coat. Remove the buttered crumbs to a bowl and set the bowl and the now-greased dish aside.

    breadcrumbs tossed in butter in casserol dish for southern squash casserole recipe

    Simply Recipes / Ciara Kehoe
  3. Steam the squash and onion, then drain:

    Put the squash and onion pieces in a large skillet with 1 cup water. Bring to a boil over high heat and cook, stirring occasionally, until the squash is tender, about 10 min.

    Strain the squash and onion into a sturdy colander in the sink. With the vegetables still in the colander, mash them with a potato masher just until they’re chunky. This allows even more moisture to drain out, which will keep your casserole from getting too watery.

    Simple Tip!

    I like this casserole with really mashed-up squash, so I cook mine until it’s mashably tender. But if that texture isn’t what you like, you can cook your squash until it’s simply cooked through and skip the mashing–just be sure to drain it really well.

    cooked sliced summer squash with onions in a pan for southern squash casserole recipe

    Simply Recipes / Ciara Kehoe
    cooked onions and summer squash mashed together in the colander for southern summer squash casserole recipe

    Simply Recipes / Ciara Kehoe
  4.  Finish the assembling the casserole:

    Beat the egg in a large bowl. Add the mayonnaise and beat until combined. Fold in the cheese, salt, and pepper. Add the mashed squash (it’s okay if it’s still hot) and mix until combined.

    mashed squash mixed with a bowlful of other ingredients for summer squash casserole recipe

    Simply Recipes / Ciara Kehoe
  5. Bake and serve: 

    Scrape into the greased dish or pan. Top evenly with the buttered cracker crumbs.

    Bake until the center is set and the crackers are lightly browned, about 30 minutes. Cool for at least 5 minutes before serving. Refrigerate leftovers for about 5 days. 

    Love the recipe? Leave us stars and a comment below!

    summer squash casserole filling topped with butered cracker pieces for southern summer squash recipe

    Simply Recipes / Ciara Kehoe
    spoonful of summer squash casserole

    Simply Recipes / Ciara Kehoe
Nutrition Facts (per serving)
249 Calories
21g Fat
9g Carbs
7g Protein
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Nutrition Facts
Servings: 8
Amount per serving
Calories 249
% Daily Value*
Total Fat 21g 26%
Saturated Fat 8g 42%
Cholesterol 60mg 20%
Sodium 408mg 18%
Total Carbohydrate 9g 3%
Dietary Fiber 1g 5%
Total Sugars 3g
Protein 7g
Vitamin C 5mg 25%
Calcium 190mg 15%
Iron 1mg 5%
Potassium 213mg 5%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
Nutrition information is calculated using an ingredient database and should be considered an estimate. In cases where multiple ingredient alternatives are given, the first listed is calculated for nutrition. Garnishes and optional ingredients are not included.