When you need something comforting, quick to throw together, and everyone will love casseroles are the answer. This recipe for squash casserole is no exception!
It’s really hard to go wrong with a mild-flavored fruit like summer squash (yes, they’re technically a fruit!) paired with a generous amount of sour cream and two types of cheese. Add an addictively crunchy crushed cracker topping tossed in a few tablespoons of butter, and you’ve got yourself a holiday side dish that will keep everyone coming back for more.
So whether you need a foolproof recipe to make for a potluck, or your holiday table needs just one more side to complement the sweet roasted delicata squash and fluffy cornbread dressing you’ve prepared, this squash casserole recipe is a must-try!
What You Need to Make This Recipe
Sour cream — sour cream helps to create a rich, creamy sauce for the casserole.
Eggs — you’ll need a couple of eggs to bind the casserole.
Yellow onion — you could swap out the yellow onion for a Vidalia onion instead for a sweeter flavor.
Yellow squash — you’ll need about 4 medium fresh squash sliced into rounds. No need to peel the squash. The thin yellow skin is edible!
Thyme — chop up some fresh thyme leaves.
Cheese — cheddar and Parmesan cheese combine with sour cream creates a decadent sauce.
Butter crackers — you’ll need about 20 buttery crackers, crushed (for example, Ritz crackers) for the crispy topping.
How to Make Squash Casserole
1. Whisk together sour cream and large eggs in a small mixing bowl. Set aside for the moment.
2. Melt unsalted butter in a large skillet or medium Dutch oven over medium heat. Add the sliced onion to the melted butter and cook. Stir occasionally and cook until the onions begin to soften and brown at the edges. This will take 4 to 5 minutes.
3. To the skillet, add kosher salt, ground black pepper, thyme, and summer squash. Cook for up to 10 minutes more, until the yellow squash is tender and the onions are very soft. Stir every now and then, but be careful not to smash the squash. You want the slices to remain mostly intact. There shouldn’t be much liquid in the skillet. If there is, drain the squash and onion mixture in a colander for a few minutes
4. Once the squash has softened, turn off the heat and pour the sour cream and egg mixture into the skillet.
5. Stir in 2 of the 3 cups of prepared grated cheddar cheese and all the grated Parmesan cheese. Stir until well incorporated. Try to make sure all the yellow squash is coated in cheese and sour cream.
6. Lightly spray an 8×8-inch casserole dish with cooking spray. Transfer the squash mixture to the dish and sprinkle the remaining cup of cheddar cheese and the cracker crumbs on top. Bake at 350°F for about 45 minutes, or until the topping is golden brown and the squash mixture is bubbling. You can loosely cover with aluminum foil if the crackers get too brown at any point during baking. Allow the squash casserole to rest for about 20 minutes before digging in.
Pro Tips for Making This Recipe
- Squash size matters. Opt for smaller yellow squash, which will be more flavorful and less watery.
- Weigh those ingredients! Weigh the yellow squash instead of guessing. You need 675 grams of squash. While this is approximately 4 medium squash, it’s better to use a kitchen scale so you have the right amount. This will give you the best squash casserole.
- Uniform squash slices helps with cooking. Cut the yellow squash so they’re as even in thickness as possible. If you have one, a mandolin is a simple way to make sure your slices are uniform.
- Don’t cut the squash too thinly. This will cause the slices to break down and become mushy.
- Don’t have yellow squash- no problem! You can swap out the yellow squash for zucchini without changing the rest of the recipe. Yellow squash and zucchini are pretty similar in terms of flavor. So aside from the color, the zucchini casserole won’t differ too much from the original recipe.
- Freshly shredded cheese is way better than the bagged stuff! If time allows, grate the cheddar cheese yourself instead of buying the pre-grated kind. Pre-grated cheese is coated with a substance called cellulose, which prevents caking and molding. While convenient, this also makes pre-grated cheese less melty.
- Try this swap for crackers. You can substitute the buttery crackers for panko breadcrumbs for a twist on the topping.
Frequently Asked Questions
Yellow squash contains a lot of water, which is released during cooking. One way to avoid excess liquid is to use smaller squash as these are usually less watery. If you use larger squash and notice the skillet has a lot of liquid, simply drop the cooked squash and onion mixture into a colander and let it drain for a few minutes.
Yellow squash casserole is a great make-ahead dish! You can prepare it the night before. Follow the recipe instructions until you add the 2 cups of cheddar cheese and Parmesan cheese. After transferring the mixture to the prepared casserole dish, stop here for now and cover the mixture and refrigerate. When you are ready to bake it, add the crushed crackers and then pop the casserole into the oven.
Store leftover summer squash casserole in an airtight container in the refrigerator for up to 4 days. The topping will lose its crunch as it sits in the fridge, and the squash may release more liquid. So I advise finishing off leftovers as soon as possible to retain as much of its delicious flavor as possible.
Yellow squash casserole takes well to being frozen and is a great way to save fresh summer squash for the winter months ahead. You can freeze it before or after baking- this is the perfect way to get a big head start on side dishes too!
If you want to freeze the casserole before baking, prepare it most of the way, but don’t add the crushed cracker topping. Instead, wrap it tightly in plastic wrap, perhaps in a few layers for added protection, and freeze for 2 to 3 months. When you are ready to serve the squash casserole, let it thaw overnight, top it with the crushed crackers, and bake.
To extend the lifespan of casserole leftovers, you can also freeze it after it’s been baked. Be sure that the squash casserole has cooled down before wrapping the baking dish in plastic wrap. Thaw it in the fridge overnight before reheating it in the oven and serving.
If you love this recipe try these out!
If you’ve tried this Squash Casserole recipe, then don’t forget to rate the recipe and let me know how you got on in the comments below, I love hearing from you!
Squash Casserole
Equipment
- mixing bowl
- 8×8″ baking dish
- Large skillet
Ingredients
- ¾ cup sour cream (180g)
- 2 large eggs
- ¼ cup unsalted butter (56g)
- ½ medium yellow onion sliced
- 1½ pounds yellow squash sliced, about 4 medium squash (675g)
- 2 teaspoons chopped thyme leaves
- ¾ teaspoon kosher salt
- ½ teaspoon ground black pepper
- 3 cups grated cheddar cheese (about 8 ounces/ 225g)
- ½ cup grated parmesan (40g)
- 20 crushed butter crackers
Instructions
- Preheat oven to 350°. Spray an 8×8-inch baking dish lightly with cooking spray.
- In a small mixing bowl, whisk together the sour cream and eggs.
- In a large skillet or medium Dutch oven over medium heat, melt the butter. Add the onions, and cook stirring occasionally, until the onions begin to soften and brown on the edges, about 4 to 5 minutes.
- Add the squash, thyme, salt, and pepper. Cook, stirring occasionally until squash is tender and onions are very soft, about 7 to 10 minutes more.
- Remove the skillet from the heat and stir in the sour cream mixture, 2 cups cheddar cheese, and Parmesan until well incorporated and the cheeses are mostly melted. Transfer the mixture to the prepared baking dish and sprinkle with the remaining cup of cheddar cheese and crushed butter crackers.
- Bake for 45 minutes or until the mixture is bubbling and the crackers are golden brown. Let the casserole rest for 15 to 20 minutes before serving.
Notes
- Squash size matters. Opt for smaller yellow squash, which will be more flavorful and less watery.
- Weigh those ingredients! Weigh the yellow squash instead of guessing. You need 675 grams of squash. While this is approximately 4 medium squash, it’s better to use a kitchen scale so you have the right amount. This will give you the best squash casserole.
- Uniform squash slices helps with cooking. Cut the yellow squash so they’re as even in thickness as possible. If you have one, a mandolin is a simple way to make sure your slices are uniform.
- Don’t cut the squash too thinly. This will cause the slices to break down and become mushy.
- Don’t have yellow squash- no problem! You can swap out the yellow squash for zucchini without changing the rest of the recipe. Yellow squash and zucchini are pretty similar in terms of flavor. So aside from the color, the zucchini casserole won’t differ too much from the original recipe.
- Freshly shredded cheese is way better than the bagged stuff! If time allows, grate the cheddar cheese yourself instead of buying the pre-grated kind. Pre-grated cheese is coated with a substance called cellulose, which prevents caking and molding. While convenient, this also makes pre-grated cheese less melty.
- Try this swap for crackers. You can substitute the buttery crackers for panko breadcrumbs for a twist on the topping.
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