This Squash Casserole is everything a comforting side dish should be: creamy, cheesy, and topped with a golden buttery cracker crust that adds just the right crunch. I first made this on a busy Tuesday night when I needed something easy but impressive enough to serve alongside grilled chicken, and it quickly became one of those recipes I turn to again and again. The tender yellow squash bakes into a savory custard with sharp cheddar and Parmesan, and the whole thing comes together in just over an hour with ingredients you probably already have.
If you're looking for more cozy sides, try pairing it with this Healthy Southern Potato Salad Recipe or serving it alongside Easy Homemade Sliders or Healthy Tomato Cracker Salad Recipe for a complete meal. It's also fantastic with other dinner recipes when you need something warm and satisfying.
The smell of caramelized onions and melted cheese fills the kitchen while this bakes, and that buttery topping gets crispy and golden in a way that makes everyone lean in for seconds.
Why You'll Love This Squash Casserole
This is one of those dishes that feels fancy but couldn't be easier. The yellow squash stays tender without getting mushy, and the combination of cheddar and Parmesan gives it a rich, savory flavor that's never bland. I love that it uses simple, everyday ingredients—no fancy cheeses or hard-to-find items—and the buttery cracker topping adds texture without overwhelming the vegetables. It's also versatile enough to serve at weeknight dinners or bring to potlucks, and it reheats beautifully if you have leftovers.
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Ingredients For Squash Casserole
Here's everything you need to make this creamy, cheesy Squash Casserole.
See Recipe Card Below This Post For Ingredient Quantities
Yellow squash: Forms the base of the casserole and provides a mild, tender vegetable that soaks up all the cheesy, savory flavors. Use about 4 cups of sliced squash.
Yellow onion: Adds sweetness and depth when caramelized, balancing the richness of the cheese and eggs.
Cheddar cheese: Provides sharp, tangy flavor and melts beautifully into the custard filling.
Parmesan cheese: Adds a nutty, salty finish and creates a golden crust on top when baked.
Garlic: Brings aromatic, savory notes that enhance the overall flavor of the dish.
Salted butter: Used to cook the vegetables and adds richness throughout the casserole.
Salt: Seasons the vegetables and custard, bringing out the natural flavors. Divided between cooking and the egg mixture.
Eggs: Bind everything together and create the creamy, custard-like texture that holds the casserole together.
Milk: Adds moisture and creaminess without being too heavy or expensive. Whole milk works best, but any variety works.
Fresh parsley: Provides a hint of freshness and color to balance the richness of the cheese and butter.
Black pepper: Adds a subtle kick and depth of flavor.
Crushed red pepper: Gives a gentle warmth and complexity without making the dish spicy.
Butter crackers: Create a crunchy, buttery topping and also get mixed into the casserole for added texture and flavor.
How To Make Squash Casserole
Follow these simple steps to make the perfect squash casserole.
Preheat the oven: Set your oven to 350°F so it's ready when you assemble the casserole. Gather your sliced yellow squash, onion, cheeses, and minced garlic.
Caramelize the onions: Melt the salted butter in a large skillet over medium heat. Add the sliced yellow onion and ¼ teaspoon of salt, then cook until the onions turn tender and golden, about 6 minutes. Stir occasionally so they don't stick.
Cook the squash: Add the yellow squash discs to the skillet and cook until they're tender but still have a slight bite, about 5 minutes. You want them al dente so they don't turn mushy when baked.
Add the garlic: Stir in the minced garlic and cook for another 2 minutes until it smells fragrant and aromatic. Then transfer everything to a 3-quart casserole dish.
Make the egg mixture: In a bowl, whisk together the eggs, milk, fresh parsley, remaining salt, black pepper, and crushed red pepper. Pour this custard mixture evenly over the cooked vegetables in the casserole dish.
Add crackers and cheese: In a separate bowl, combine half of the crushed butter crackers with the shredded cheddar cheese. Mix well, then gently stir this mixture into the casserole so it's distributed throughout.
Top the casserole: Sprinkle the remaining crushed crackers evenly over the top, then finish with the shredded Parmesan cheese for a golden, crispy crust.
Bake: Place the casserole in the preheated oven and bake for 45 minutes, or until the top is golden brown and the edges are bubbly. The center should be set and not jiggly.
Cool slightly: Let the casserole rest for about 5 minutes before serving. This helps it set up and makes it easier to scoop.
Substitutions and Variations
This Squash Casserole is flexible and easy to customize based on what you have on hand.
Squash: You can swap yellow squash for zucchini, or use a mix of both. They cook similarly and taste great together.
Cheese: Try Gruyère, Monterey Jack, or a sharp white cheddar if you want to switch up the flavor. Parmesan can be replaced with Asiago or Pecorino Romano.
Milk: Heavy cream will make this richer, while 2% milk keeps it lighter. Non-dairy milk like almond or oat milk works in a pinch.
Crackers: Ritz crackers are classic, but you can use any buttery cracker you prefer. Even crushed breadcrumbs or panko will work for the topping.
Add protein: Stir in cooked, crumbled bacon or diced ham to make this more substantial.
Herbs: Fresh thyme, basil, or chives add brightness. You can also use dried Italian seasoning if fresh herbs aren't available.
Equipment For Squash Casserole
You don't need much to make this casserole, just a few basic kitchen tools.
Large skillet: For cooking the onions, squash, and garlic before assembling the casserole.
3-quart casserole dish: Holds all the ingredients and bakes evenly. A 9x9-inch or similar-sized baking dish works too.
Mixing bowls: One for the egg mixture and one for combining crackers and cheese.
Whisk: To mix the eggs and milk smoothly.
Wooden spoon or spatula: For stirring the vegetables and combining ingredients.
Storage and Reheating Tips
This Squash Casserole stores well and tastes just as good the next day.
Refrigerator: Store leftovers in an airtight container for up to 4 days. The flavors actually deepen overnight, so it's great for meal prep.
Freezer: You can freeze this casserole before or after baking. Wrap it tightly in plastic wrap and aluminum foil, then freeze for up to 3 months. Thaw overnight in the fridge before reheating.
Reheating: Warm individual portions in the microwave for 1-2 minutes, or reheat the whole casserole covered with foil in a 350°F oven for about 20 minutes until heated through.
Serving Suggestions
This squash casserole pairs beautifully with so many dishes.
Serve it alongside roasted chicken or grilled pork chops for a comforting weeknight dinner. It's also perfect with Sunday pot roast or baked ham, especially during the holidays. For a lighter meal, pair it with a simple green salad and crusty bread. I also love serving this at potlucks and family gatherings—it travels well and always disappears quickly.
Expert Tips
These small tricks make a big difference in how your casserole turns out.
Don't overcook the squash: Cooking the squash just until al dente before baking prevents it from getting too soft and watery in the oven.
Let the onions caramelize: Taking the time to properly caramelize the onions adds sweetness and depth that makes this dish special.
Use room temperature eggs: This helps them blend smoothly into the milk mixture and creates a more even custard.
Crush crackers to different sizes: A mix of fine crumbs and slightly larger pieces gives the topping more texture and crunch.
Let it rest: Allowing the casserole to sit for 5 minutes after baking helps it set up so it's easier to serve without falling apart.
Taste and adjust seasoning: Before baking, taste a bit of the egg mixture and adjust salt and pepper to your preference.
FAQ
What are the ingredients for squash casserole?
This Squash Casserole uses yellow squash, onion, cheddar and Parmesan cheeses, eggs, milk, butter, garlic, seasonings, and butter crackers. It's a simple combination that creates a creamy, cheesy dish with a crunchy topping.
What are some common mistakes in squash casserole?
The biggest mistake is overcooking the Squash Casserole before baking, which makes it mushy. Also, skipping the step of caramelizing the onions means you'll miss out on sweetness and depth. Finally, not letting the casserole rest after baking can make it too loose and hard to serve cleanly.
What is Jackie Kennedy's casserole?
Jackie Kennedy's famous Squash Casserole was actually a seafood dish made with crab and lobster, not a vegetable casserole. It's quite different from this squash casserole, though both are rich, comforting baked dishes.
What are some tips for making the best squash casserole?
Use fresh Squash Casserole and slice it evenly so everything cooks at the same rate. Caramelize your onions properly, don't skip the garlic, and make sure to divide your cracker crumbs between the filling and topping. Letting the casserole rest after baking is also key for clean slices.
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Pairing
These are my favorite dishes to serve with Squash Casserole
Squash Casserole
Ingredients
- 2-3 yellow squash sliced into ¼-inch discs, about 4 cups
- ½ yellow onion finely sliced
- ¾ cup cheddar cheese shredded
- ¼ cup Parmesan cheese shredded
- 3 cloves garlic minced
- 2 tablespoon salted butter
- 1 teaspoon salt divided
- 2 eggs
- ½ cup milk any type, such as whole or 2%
- ½ tablespoon fresh parsley chopped
- ½ teaspoon black pepper freshly cracked
- ¼ teaspoon crushed red pepper
- 18 butter crackers crushed, divided
Instructions
- Preheat the oven to 350°F. Gather all ingredients: yellow squash, onion, shredded cheddar, Parmesan, and minced garlic.
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In a large skillet, melt the butter over medium heat. Add the onion and ¼ teaspoon salt. Cook until the onion is tender and starts to caramelize, about 6 minutes.
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Add the squash slices to the skillet and cook for 5 minutes, or until tender-crisp.
- Stir in the minced garlic and cook for an additional 2 minutes until fragrant.
- Transfer the cooked vegetables into a 3-quart casserole dish.
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In a separate bowl, beat the eggs and mix with the milk, parsley, remaining salt, black pepper, and crushed red pepper. Pour this mixture over the vegetables in the casserole dish.
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Combine half of the crushed crackers and shredded cheddar in a bowl. Stir well to combine, then add this mixture to the casserole dish with the squash.
- Top the casserole with the remaining crushed crackers and sprinkle with Parmesan cheese.
- Bake the casserole in the preheated oven for 45 minutes, or until the top is golden brown and crispy.
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