Rich Yellow Squash and Corn Casserole

If you ask me, summer produce deserves a spot at the dinner table beyond just grilled vegetables.

This yellow squash and corn casserole is a comforting side dish that brings together the best of garden-fresh vegetables. Tender squash and zucchini cook down in chicken broth until they’re soft and flavorful, then get mixed with sweet corn kernels.

The whole thing is held together with a creamy mixture of mayo, sour cream, and eggs, then topped with sharp cheddar cheese. A buttery Ritz cracker crust adds that perfect crunchy finish on top.

It’s a family-friendly dish that works just as well for weeknight dinners as it does for potlucks and holiday gatherings.

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What Kind of Yellow Squash Should I Use?

Any variety of yellow squash will work great in this casserole, whether you grab straightneck or crookneck squash at the store. Look for squash that feels firm and heavy for its size, with smooth, unblemished skin that has a nice shine to it. Smaller to medium-sized squash tend to have fewer seeds and a sweeter flavor than the really large ones, so aim for squash that are about 6-8 inches long if you can. If your squash seems particularly watery or seedy, you can scoop out some of the seeds from the center before slicing, but it’s usually not necessary with younger, smaller squash.

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Options for Substitutions

This casserole is pretty forgiving when it comes to swapping ingredients:

• Yellow squash and zucchini: You can use all yellow squash or all zucchini if that’s what you have – the total should still be about 8 cups. Some folks even throw in a cup or two of sliced mushrooms for extra flavor.
• Corn: Fresh, frozen, or canned corn all work here. If using canned, just drain it well before adding. You can also use about 4 ears of fresh corn if you want to go that route.
• Mayonnaise: Greek yogurt makes a good substitute if you’re looking for something lighter. You can also use all sour cream instead – just use 1 cup total.
• Sharp cheddar cheese: Mild cheddar, Monterey Jack, or a Mexican cheese blend work just fine. You could even mix in some Parmesan for extra flavor.
• Ritz crackers: Crushed butter crackers, panko breadcrumbs, or even crushed cornflakes make good topping alternatives. Just add a tablespoon of melted butter to whatever you use for that buttery crunch.
• Chicken broth: Vegetable broth works perfectly here, or you can even use water in a pinch – the casserole will still have plenty of flavor from the other ingredients.

Watch Out for These Mistakes While Baking

The biggest mistake when making this casserole is not draining the vegetables thoroughly after simmering, which leads to a watery, soupy dish instead of a creamy one – press the cooked squash and zucchini gently with a spoon or let them sit in a colander for a few minutes to remove excess liquid.

Overcooking the vegetables during the initial simmer is another common error, so keep an eye on them and pull them off the heat as soon as they’re tender since they’ll continue cooking in the oven.

To keep your Ritz cracker topping crispy rather than soggy, wait until the last 10 minutes of baking to add the final layer of crackers and cheese, or mix the melted butter directly with the crackers before sprinkling them on top.

Finally, let the casserole rest for about 10 minutes after baking so it can set up properly and won’t fall apart when you scoop it out to serve.

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What to Serve With Yellow Squash and Corn Casserole?

This casserole is pretty hearty on its own, so I like to keep the sides simple and let it be the star of the meal. Grilled chicken, pork chops, or even a basic baked chicken breast pair really well since the casserole brings all the flavor and creaminess you need. If you’re firing up the grill, some BBQ ribs or pulled pork would be amazing alongside this dish – it’s got that Southern comfort food vibe that goes perfectly with smoky meats. A light cucumber and tomato salad or some quick pickled vegetables can help balance out the richness of all that cheese and sour cream.

Storage Instructions

Store: Keep any leftover casserole covered tightly with foil or in an airtight container in the fridge for up to 4 days. The flavors actually meld together nicely after a day, so don’t be surprised if it tastes even better the next day!

Freeze: This casserole freezes pretty well for up to 2 months. I recommend freezing it before baking for best results, or you can freeze leftovers in individual portions. Just wrap it tightly in plastic wrap and then foil to prevent freezer burn.

Reheat: Warm up individual portions in the microwave for about 2 minutes, or reheat the whole dish covered with foil in a 350°F oven for 20-25 minutes until heated through. If the crackers get a bit soft after storing, you can always sprinkle some fresh crushed Ritz on top before reheating.

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 2200-2400
• Protein: 70-80 g
• Fat: 130-150 g
• Carbohydrates: 200-220 g

Ingredients

For the vegetable base:

• 4 cups yellow squash (cut into 1/2-inch thick half-moons)
• 4 cups zucchini (sliced into 1/2-inch thick rounds)
• 1 1/2 cups onion
• 4 cups chicken broth (I use Swanson Less Sodium for better salt control)
• 2 cups corn

For the binder:

• 1/2 cup mayonnaise (I prefer Duke’s for its tangy flavor)
• 1/2 cup sour cream
• 2 eggs (room temperature, about 70°F, for smoother mixing)
• 3 tbsp butter, melted
• 1 tsp salt
• 3/4 tsp black pepper
• 1/2 tsp garlic powder
• 1 tsp fresh thyme leaves
• 1 1/2 cups cheddar cheese (freshly grated for better melting)

For the topping:

• 1 1/2 cups crackers (I use Ritz for the most buttery crunch)
• 1/2 cup cheddar cheese

Step 1: Prepare Mise en Place and Preheat

• 4 cups yellow squash
• 4 cups zucchini
• 1 1/2 cups onion
• 1 1/2 cups crackers
• 1 1/2 cups cheddar cheese

Preheat your oven to 350°F and lightly grease a 9×13 inch baking dish.

While the oven preheats, cut the yellow squash into 1/2-inch thick half-moons, slice the zucchini into 1/2-inch thick rounds, and dice the onion into roughly 1/4-inch pieces.

Crush the Ritz crackers into bite-sized crumbs (not too fine—you want texture).

Grate the 1 1/2 cups of cheddar cheese if not already done, and measure out all remaining ingredients so everything is ready to go.

Step 2: Simmer Vegetables Until Tender

• 4 cups chicken broth
• yellow squash from Step 1
• zucchini from Step 1
• onion from Step 1
• 2 cups corn

In a large pot, bring the chicken broth to a boil over medium-high heat.

Add the prepared squash, zucchini, and onion, then reduce heat to medium and simmer for 6-7 minutes until the vegetables are just tender but not mushy.

Drain the vegetables thoroughly in a colander, discarding the broth.

Stir the drained vegetables together with the corn in a large bowl.

Step 3: Create the Creamy Binder

• 1/2 cup mayonnaise
• 1/2 cup sour cream
• 2 eggs
• 3 tbsp butter, melted
• 1 tsp salt
• 3/4 tsp black pepper
• 1/2 tsp garlic powder
• 1 tsp fresh thyme leaves
• 1 1/2 cups cheddar cheese

In a medium bowl, whisk together the mayonnaise, sour cream, and room-temperature eggs until smooth and fully combined.

This creates a silky base that will bind everything together.

Stir in the melted butter, salt, black pepper, garlic powder, and fresh thyme leaves until evenly distributed.

Finally, fold in the 1 1/2 cups of freshly grated cheddar cheese.

I like to reserve a bit of this creamy mixture to swirl through the middle of the casserole for extra richness.

Step 4: Combine and Layer the Casserole

• creamy binder from Step 3
• vegetable and corn mixture from Step 2
• cracker crumbs from Step 1
• 1/2 cup cheddar cheese

Pour the creamy binder from Step 3 over the vegetable and corn mixture from Step 2, stirring gently until everything is evenly coated.

Spread half of this combined mixture into the prepared baking dish, creating an even layer.

Sprinkle half of the cracker crumbs over this first layer, then add the remaining vegetable mixture on top.

Finally, top with the remaining cracker crumbs and the 1/2 cup of additional cheddar cheese for a golden, cheesy finish.

Step 5: Bake Until Golden and Bubbly

Bake in the preheated 350°F oven for 25 minutes until the top is golden brown and the casserole is bubbling around the edges.

The cheese should be melted and the crackers lightly crisped.

Let the casserole rest for 5 minutes before serving—this helps it set slightly and makes portioning cleaner.

Rich Yellow Squash and Corn Casserole

Delicious Rich Yellow Squash and Corn Casserole recipe with step-by-step instructions.

Print Recipe Pin Recipe

Prep Time 15 minutes mins

Cook Time 35 minutes mins

Total Time 52 minutes mins

Servings 8 servings

Calories 2300 kcal

Ingredients

  

For the vegetable base

• 4 cups yellow squash (cut into 1/2-inch thick half-moons)
• 4 cups zucchini (sliced into 1/2-inch thick rounds)
• 1 1/2 cups onion
• 4 cups chicken broth (I use Swanson Less Sodium for better salt control)
• 2 cups corn

For the binder

• 1/2 cup mayonnaise (I prefer Duke's for its tangy flavor)
• 1/2 cup sour cream
• 2 eggs (room temperature, about 70°F, for smoother mixing)
• 3 tbsp butter, melted
• 1 tsp salt
• 3/4 tsp black pepper
• 1/2 tsp garlic powder
• 1 tsp fresh thyme leaves
• 1 1/2 cups cheddar cheese (freshly grated for better melting)

For the topping

• 1 1/2 cups crackers (I use Ritz for the most buttery crunch)
• 1/2 cup cheddar cheese

Instructions

 

• Preheat your oven to 350°F and lightly grease a 9x13 inch baking dish. While the oven preheats, cut the yellow squash into 1/2-inch thick half-moons, slice the zucchini into 1/2-inch thick rounds, and dice the onion into roughly 1/4-inch pieces. Crush the Ritz crackers into bite-sized crumbs (not too fine—you want texture). Grate the 1 1/2 cups of cheddar cheese if not already done, and measure out all remaining ingredients so everything is ready to go.
• In a large pot, bring the chicken broth to a boil over medium-high heat. Add the prepared squash, zucchini, and onion, then reduce heat to medium and simmer for 6-7 minutes until the vegetables are just tender but not mushy. Drain the vegetables thoroughly in a colander, discarding the broth. Stir the drained vegetables together with the corn in a large bowl.
• In a medium bowl, whisk together the mayonnaise, sour cream, and room-temperature eggs until smooth and fully combined. This creates a silky base that will bind everything together. Stir in the melted butter, salt, black pepper, garlic powder, and fresh thyme leaves until evenly distributed. Finally, fold in the 1 1/2 cups of freshly grated cheddar cheese. I like to reserve a bit of this creamy mixture to swirl through the middle of the casserole for extra richness.
• Pour the creamy binder from Step 3 over the vegetable and corn mixture from Step 2, stirring gently until everything is evenly coated. Spread half of this combined mixture into the prepared baking dish, creating an even layer. Sprinkle half of the cracker crumbs over this first layer, then add the remaining vegetable mixture on top. Finally, top with the remaining cracker crumbs and the 1/2 cup of additional cheddar cheese for a golden, cheesy finish.
• Bake in the preheated 350°F oven for 25 minutes until the top is golden brown and the casserole is bubbling around the edges. The cheese should be melted and the crackers lightly crisped. Let the casserole rest for 5 minutes before serving—this helps it set slightly and makes portioning cleaner.