This scrumptious Squash Casserole is a crowd-pleaser. Featuring sliced yellow squash, onions, and a cheesy sour cream sauce, this casserole is a comforting and flavorful addition to any meal. Topped with a crunchy layer of buttery Ritz crackers, it adds the perfect finishing touch to this irresistible dish.
A sour cream squash casserole with Ritz crackers checks every box on your side dish list: It’s incredibly flavorful, layered with a tangy cheesy sauce, and has a crunchy Ritz cracker topping.
With summer squash showing up in the farmer’s market and in summer gardens, it’s always nice to have a few squash recipes to pull out. Some of my other favorites squash recipes are a Tex-Mex squash casserole , squash topped with biscuits and squash casserole with pasta. This Southern squash casserole recipe has a sour cream-mayo cheese sauce that really sets it apart.
Some people shy away from squash casseroles because the texture can be mushy. Unlike some summer squash casseroles, this one doesn’t get soggy because you partially cook the squash before you assemble the casserole, a secret technique for retaining a superior texture. It’s a technique I use when making pasta and squash casserole also.
This creamy casserole might look plain but with a sauce made up of sour cream, mayo, parmesan, Gruyere, and cheddar it’s much better than the one your grandmother made. It’s a scaled up version of an old-fashioned recipe that’s easy to put together.
Perfect for a show-stopping holiday side dish, this might just be your new signature Thanksgiving recipe. Keep it in mind for your next potluck. If you’ve ever thought of squash as boring, you won’t any longer! Serve it alongside green bean casserole, mashed potatoes, and cornbread biscuits for a balanced (and beautiful looking) table of sides.
Why you’ll love this recipe for Squash Casserole
- It has a beautiful texture – perfectly cooked and covered in a tangy, cheesy sour cream sauce, with nicely baked and not-at-all mushy squash.
- The cheese sauce is incredibly flavorful – this recipe uses sour cream, gruyere, mayo, and cheddar to make the yummiest filling.
- It’s topped with Ritz crackers. You can’t beat the buttery flavor of Ritz, and they provide the perfect amount of crunch for a delightful blend of textures.
Squash Casserole Recipe Ingredients
- Yellow Squash – Look for a squash that’s medium-sized with bright yellow skin. Your squash should feel firm without any squishy spots, and it should be heavy for its size. Replace the yellow squash with zucchini if you’d like, or use a mixture of both.
- Ritz Crackers – I prefer the original variety for this recipe. If you needed to replace the Ritz crackers, you could use another kind of buttery crackers or a panko breadcrumbs.
- Vidalia Onion – Vidalias are sweet and provide a mild onion flavor without overpowering the dish.
- Cheddar and Gruyere – These cheeses need to be shredded. I highly recommend shredding your own cheese because it will melt much better.
- Parmesan – A fresh block of parmesan will add so much flavor. Don’t use powdered parmesan.
- Sour Cream – I always prefer full-fat, but you can use low-fat sour cream if you want. You can also use plain Greek yogurt for a bit of a different flavor.
- Mayonnaise – Mayo provides a lot of tanginess in this recipe. However, if you can’t use it, you can replace it with plain Greek yogurt.
- Fresh Thyme and Parsley – Look for bright leaves without the presence of any wilting or brown spots
- Pantry Staples – Butter, salt, egg
What is Gruyere?
Gruyere is a lesser-known semi-hard cheese variety that, if you’ve never used it, should be on your must-try list. It’s a Swiss cheese (but without the holes) that is aged for at least 6 months.
Gruyere melts incredibly stringy. It has a high water-to-oil ratio, a quality that causes it to melt better than many other cheeses. It’s the cheese typically found on the top of a bowl of French onion soup, and it’s often added to cheese fondues and charcuterie boards because of its rich flavor.
If you need to substitute the Gruyere in this recipe, try Emmental, Beauforte, Fontina, or, in a pinch, good old Swiss.
What’s the difference between yellow squash and zucchini?
‘Squash’ is a very broad term that is the family name for a whole slew of vegetables, including zucchini. There are plenty of different varieties of squash, like yellow squash (what’s used in this recipe), butternut squash, acorn squash, and the classic spaghetti squash. The easiest way to tell a zucchini apart from other squash is that zucchini is long and thin, and is typically dark green.
In this recipe, you can use zucchini instead of yellow squash or use a mixture of both.
Squash Casserole with Ritz Crackers substitutions and variations
You can substitute greek yogurt for the sour cream or mayonnaise.
Instead of Ritz Crackers you can combine 2 tablespoons of melted butter with 1 cup of panko crumbs.
You can use zucchini squash instead of summer squash or a combination of both.
How to make Squash Casserole
Step 1: Pre-cook the squash.
Slice the squash then saute the squash and the onion in butter for about 10 minutes, until the squash is just beginning to soften. Drain well. This step will get rid of the excess liquid.
Step 2: Prepare the creamy sauce.
Use a whisk to combine the eggs, sour cream, mayo, cheddar, gruyere, and seasoning. Fold in the squash, and spoon the mixture into a baking dish.
Step 3: Prepare the topping and bake.
Combine the Ritz crackers with melted butter, parmesan, and parsley. Sprinkle the buttery cracker crumbs over the casserole and bake until the top is golden brown.
Tips for making this recipe for Squash Casserole
- To prevent a watery casserole, the squash shouldn’t be overcooked or undercooked. Wait for the squash to be just soft enough to begin to pierce with a fork, and remove it from the skillet.
- Let the Ritz crackers soak up the butter before putting them on top of the casserole.
- Try to keep the slices of squash the same thickness.
Summer Squash Casserole storage
If you have leftovers, transfer them to a smaller airtight container or cover with plastic wrap and place them in the fridge. Your casserole should be good for up to 3 days.
To reheat leftovers, microwave them, or place them in the oven in a baking dish at 350°F until hot through, about 10-15 minutes.
Can you freeze cooked squash casserole?
Yes, you can freeze this casserole either before it has baked or after. Wait to add the topping until prior to baking if freezing before it has baked. It should last in the freezer for about 3 months in an airtight container.
Yellow Squash Casserole FAQs
Can I make squash casserole ahead?
This casserole is best fresh and shouldn’t be baked ahead and frozen to serve later. But you can assemble your casserole and refrigerate it before baking. However, I wait to add the topping until right before baking.
Do you peel squash before baking?
No, you should not peel the squash. Give it a good scrub using water and your hands. The peel is crucial as it holds the squash flesh together. Without it, the squash would fall apart and become mushy as it begins to cook.
Is squash good for you?
Everyone’s dietary needs are different, but generally speaking, squash is considered a healthy food. It’s full of vitamins and minerals and has very little calories or fat.
What else can I use to top a squash casserole?
Instead of Ritz crackers, you can use panko bread crumbs or any other type of buttery cracker. The crispy topping is a nice contrast to the soft filling.
How do you keep squash casserole from getting watery?
Squash contains plenty of water. If you bake squash in the water will seep out during cooking and make your dish watery. If your dish contains a sauce, the sauce will end up watered down as well.
To properly bake a squash casserole without it getting watery, you need to remove some of the water before you assemble it. You can par-cook your squash first by sauteeing it in a pan. This will release a good portion of the water. Remove the squash before it’s fully cooked, then let it finish cooking while the casserole bakes.
More Vegetable Casseroles to Love
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Yellow Squash Casserole Recipe
- 3 tablespoons butter
- 6 cups yellow squash about 3 medium-sized squash
- ½ medium vidalia onion chopped
- 1 teaspoon salt
- 1 egg lightly beaten
- 4 ounces sharp cheddar cheese ½ cup shredded
- 2 ounces gruyere ¼ cup shredded
- ½ cup sour cream
- ¼ cup mayonnaise
- 1 teaspoon fresh thyme
- ½ sleeve Ritz crackers
- 2 tablespoon butter
- 2 tablespoon parmesan cheese finely grated
- 1 teaspoon parsley chopped
- Saute pan
- Preheat oven to 350º. Lightly butter a 2 quart baking dish.
- Melt 1 ½ tablespoons of butter in a large skillet. Add sliced squash and chopped onions and ½ teaspoon salt. Cook over medium heat, stirring often until the squash is no longer firm but is not mushy. This will take about 10 minutes depending on how much moisture is in the squash.
- Add the squash mixture to a colander to drain any additional liquid.
- In a large bowl, whisk together the eggs, sour cream, mayonnaise, cheddar and gruyere, thyme, ½ teaspoon salt and pepper. Gently fold in the partially cooked squash and onions. Spoon into the prepared baking dish.
- În a small bowl or measuring cup, melt the butter and add crushed crackers, parmesan and parsley. Mix with a fork then sprinkle over the top of the squash.
- Bake for 20 minutes or until the top is golden brown.
Barbara’s Tips + Notes
- For this casserole to be not watery or mushy, the squash can’t be overcooked or undercooked.
- You can use panko breadcrumbs instead of crackers.
- You can use zucchini instead of yellow squash or use a mixture of both.