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Summer Squash Casserole

Creamy, cheesy squash casserole with toasted buttery breadcrumbs, a comforting side dish that’s perfect for using fresh summer yellow squash.

Overhead view of baked squash casserole showing a spoonful.

I love fresh seasonal produce, especially all the tomatoes, sweet corn, peppers and cucumbers of summer.  Yellow squash, not so much.  I used to get a weekly CSA box from a local farm and kind of dreaded the abundance of kohlrabi, yellow squash and bok choy.

Well, I would love and welcome the bok choy now.  In one delivery they included a recipe for a casserole that used yellow squash, and that recipe turned me into a fan.

Close up od spoonful of yellow suash casserole.

I think maybe it’s the texture of cooked summer squash I don’t care for because it can easily be mushy.  In this casserole the squash is sautéed and then puréed in a food processor, then it’s combined with the other ingredients and baked, no mushy and seedy slices.  And tons of yummy flavor.


Yellow squash with slices.

  • Fresh yellow squash
  • Onion
  • Monterey Jack cheese and sour cream
  • An egg
  • Dry white wine or vermouth
  • Salt, sugar and hot sauce
  • Fresh bread crumbs and butter


Cooking yellow squash in pan.

  • Cook onion in butter until softened, transfer to a bowl.
  • Add more butter and then sauté the sliced squash until tender.

Three photo process collage, assembling casserole.

  • Add squash to food processor and pulse until fairly smooth.  Transfer to a bowl and add the onions and remaining ingredients, mix to combine, transfer to buttered baking dish.
  • Melt butter in small sauce pan, add fresh bread crumbs and toast until golden, sprinkle over squash mixture.

Baked casserole in white dish.

  • Bake for about 30 minutes, sprinkle with fresh chopped parsley and serve.


  • Slice the squash thinly and evenly, I use a mandolin to make this task quick and easy.
  • I used white wine but you could also use vermouth.  It’s just a couple tablespoons and it really makes a difference in the flavor profile of this casserole.
  • Freshly grated cheese is best, it tastes and melts better.
  • For fresh bread crumbs, I pulse a piece of French baguette in the food processor until I get some rustic looking crumbs.  Any hearty white bread will work.  Watch carefully so as not to burn when toasting in the butter.
  • Don’t overcook the squash before processing, you just want the moisture cooked out and starting to soften.

This summer squash casserole with sour cream and cheese really is one of my favorite ways to use fresh yellow squash.  Comforting, creamy and full of fresh flavor, it’s the perfect summer side dish.  Super happy for the recipe from the farm so many years ago, it’s a keeper.  Enjoy, Kelly🍴🐦

Spoonful of casserole over baking dish.

Here are are a few of my favorite fall and winter squash recipes you might want to try:

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Overhead view of baked squash casserole showing a spoonful.

Summer Squash Casserole

Creamy, cheesy squash casserole with toasted buttery breadcrumbs, a comforting side dish that's perfect for using fresh summer yellow squash.
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Course: Side Dish
Cuisine: American
Prep Time: 15 minutes
Cook Time: 45 minutes
Total Time: 1 hour
Servings: 6
Author: Kelly Wildenhaus | the hungry bluebird


  • tablespoons unsalted butter, divided
  • 1 small onion, finely diced
  • 1 pound yellow summer squash, thinly sliced about 3 medium squash
  • ½ cup grated Monterey Jack cheese
  • 1 egg, lightly beaten
  • ½ cup sour cream
  • 2 tablespoons dry white wine or vermouth
  • ½ teaspoon kosher salt
  • ½ teaspoon sugar
  • Dash or two hot pepper sauce
  • ½ cup fresh bread crumbs
  • 1 tablespoon chopped fresh parsley


  • Preheat oven to 350º.
    Melt 1 tablespoon butter in large skillet over medium-low heat. Add diced onion and cook until translucent, about 5 minutes. Transfer to small bowl and set aside.
  • Add 2 more tablespoons of butter to pan over medium-high heat and add squash. Cook and stir frequently until moisture has evaporated and squash is just tender, about 10 minutes. Transfer to a food processor and pulse until fairly smooth.
  • Transfer processed squash to a large bowl and add onions and all remaining ingredients except bread crumbs and parsley. Mix well and transfer to a small, round buttered baking dish.
  • Melt remaining 1½ tablespoons butter in a small saucepan over medium-high heat. Stir in fresh bread crumbs and cook and stir frequently until golden brown. Sprinkle over squash mixture. Bake for 30 to 35 minutes until hot and bubbly around the edges. Sprinkle with parsley and serve. Enjoy!
Keyword: Squash casserole, yellow squash casserole, with sour cream, with cheese
Did you make this recipe? Please comment, rate it and share! And mention me on Instagram @thehungrybluebird or tag #thehungrybluebird so I can see!
Recipe Rating


Sunday 4th of April 2021

I am wondering if you can help me understand what I did wrong. I feel like I followed your instructions and timings to a tee, but the dish ended up completely liquid and never cooking through. Should I perhaps have drained the squash? I didn't think I cooked them so much that they were mush, but the blended squash was quite loose already.


Monday 12th of July 2021

I'm sorry to hear that, Theo. I'm not sure what happened, that has not happened to me. It always cooks and looks like the photos in the post. Maybe your squash had a high water content and needed to sauté longer until more of the liquid evaporated. You could also try draining it in a colander if the water seems excessive before adding it to the food processor.


Tuesday 6th of July 2021

@Theo, the same thing happened to me! I cooked it a little longer and put in the fridge overnight and it solidified a bit.


Wednesday 22nd of July 2020

Best tasting and use of a yellow squash ever.