Easy Creamy Squash Casserole

Easy Creamy Squash Casserole

Yellow squash combined with cheddar cheese, creamy mayonnaise, butter, onion, bell pepper, and celery and baked till golden brown.  A perfect blend of seasonings adds amazing flavor.  The best squash casserole! 


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Welcome to My Kitchen Serenity!  I’m excited to share with you this creamy squash casserole.  While it’s perfect for the holidays, like Thanksgiving and Christmas, we eat it year-round because it’s an easy and delicious side dish.


This side dish is one of our all time favorites!  We love all kinds of squash recipes.  Try my stuffed spaghetti squash recipe that’s a delicious main dish!


This wonderful casserole doesn’t have a cracker or bread crumb topping.  It’s rich and creamy as is.  Being that it doesn’t have any kind of topping, it’s also a fantastic low carb vegetable casserole.  Your low carb family and friends will definitely be happy to see this one on the table!


squash casserole ingredients


Short Cut Tip:  To make this recipe really easy, I use the frozen seasoning blend.  This blend consists of chopped onion, bell pepper, and celery.  I keep a bag or two in my freezer at all times.  It’s great for casseroles, chili, soup, omelets, etc.


Traditional southern recipes usually call for a Ritz cracker topping.  While I do love a cracker topping, I honestly like this casserole without cracker crumbs.  Plus, it’s a nice addition on the table next to the other casseroles that have toppings.



This easy recipe happens to be low carb, keto, gluten-free, grain-free, and sugar-free.  It’s creamy and cheesy texture will make you want seconds!  It’s a really good side dish option for most main dishes. 


Here in the south, fresh squash is available at any time of the year.  However, frozen squash is a good substitute.  We will boil the fresh (or frozen) squash for only 5 minutes. Be sure to thoroughly drain the cooked squash.  I like to let it sit in the colander while I’m preparing the rest of the recipe.


baked squash casserole with cheese


Ingredients for Yellow Squash Casserole

please refer to the recipe card for detailed ingredients and helpful information

  • Fresh or Frozen Yellow Squash
  • Frozen chopped onion, bell pepper, and celery blend
  • Cheddar Cheese
  • Butter
  • Mayonnaise
  • Seasonings:  pepper, garlic powder, chicken bouillon


How to Make Yellow Squash Casserole

please refer to the recipe card for detailed directions and how-to photos.  You can also print the recipe card with or without the photos.

  • In a nutshell, you will boil the squash and drain it.
  • Saute the veggies in butter; then add mayo and seasonings.
  • Combine all in a skillet or casserole dish and bake.  Enjoy 🙂

quartered squash in pot of water

sauteed onion-bell pepper-celery in skillet

unbaked squash casserole

baked squash in cast iron skillet with shredded cheese on top


Substitutions and Additions

Zucchini instead of yellow squash

Pepper jack cheese instead of cheddar

Olive oil instead of butter

Use a can of diced green chilis, drained

Buttered cracker crumb or bread topping before baking


Other Side Dishes

Easy Spinach Parmesan Casserole

Oven Roasted Carrots

Creamy Cabbage Casserole

Fresh Zucchini Pie

Baked Beans with Ground Beef and Bacon


Storing Leftovers

Store leftovers in airtight containers for up to 3 days.  I like to use BPA-free glass containers with locking lids.  Check out this 18-piece set of glass food storage containers with locking lidsAvailable now on Amazon.


Make Ahead Casserole

Make the casserole the day before you serve it.  Store covered in the refrigerator.  Then bake as directed the next day.  I would let the casserole come to room temperature before placing the casserole dish into a hot oven.


If you try this delicious squash recipe, please let me know in the comments below. 

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baked squash casserole in skillet

Easy Squash Casserole

Fresh yellow squash combined with butter, cheddar cheese, and mayonnaise creates the best squash casserole!  A perfect blend of seasonings adds amazing flavor.
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Course: Side Dish
Cuisine: American
Prep Time: 10 minutes
Cook Time: 35 minutes
Total Time: 45 minutes
Servings: 4
Calories: 192kcal


  • Sharp kitchen knife
  • Cutting board
  • large pot
  • colander
  • measuring spoons
  • measuring cup
  • Casserole dish or skillet


  • 1-1/2 lbs yellow squash (fresh or frozen)
  • 1 tbsp salted butter
  • 1/2 cup frozen chopped onion, bell pepper, and celery mixture
  • 1/4 cup full fat mayonnaise
  • 1 tsp chicken flavored bouillon base comes in a jar; Better than Bouillon Roasted Chicken is what I use
  • 1/4 tsp garlic powder
  • 1/8 tsp pepper
  • 1 cup shredded cheddar cheese
  • fresh parsley for garnish
  • salt (test flavor before baking, add salt if needed)


  • Preheat oven to 350F.
  • Place the sliced squash into a large pot. Add just enough water to cover squash. Bring to a boil, then lower heat and simmer the squash for 5 minutes. Drain squash in a colander and let it stay in the colander for now.
  • Melt butter in a small skillet. Add the frozen chopped onion, bell pepper, and celery mixture. Simmer on medium-low heat for 5 minutes or until tender. Turn off heat. Add mayonnaise, chicken bouillon, garlic powder, and pepper. Mix well.
  • Add cooked squash and cheese to skillet. Mix well. Taste test for flavor and add salt, if desired.
  • Bake uncovered for 30-35 minutes, or until slightly browned. Garnish with fresh parsley and extra cheese if desired.


Use a mini food chopper to finely mince the onion and celery.  I use this Mini Chopper from Proctor Silex.  Available now on Amazon.  The recipe can be doubled and baked in a 9" x 13" baking dish.
Can be baked in a small casserole dish.
Tried this recipe?Mention @mykitchenserenity or tag #mykitchenserenity on Instagram!!


Serving: 5.4oz | Calories: 192kcal | Carbohydrates: 4g | Protein: 6g | Fat: 17.3g | Saturated Fat: 7.2g | Trans Fat: 0.4g | Cholesterol: 33mg | Sodium: 217mg | Fiber: 1g | Sugar: 3g

If you try this recipe, let me know.  I’d love to hear from you!









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