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 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!


To make this recipe really easy, I use the frozen seasoning blend.  This blend consists of chopped onion, bell pepper, and celery.  I keep at 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.


It was a beautiful day outside, so I thought I’d take a quick picture on the patio.  I picked some fresh parsley to garnish the casserole.  Our dog, Jax, didn’t understand why I was in his backyard with no tennis ball, lol.


baked casserole


Quick Peek at the Ingredients

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



  • 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 casserole dish and bake.  Enjoy 🙂



Zucchini instead of yellow squash

Pepper jack cheese instead of cheddar

Olive oil instead of butter

Use a can of diced green chilis, drained, instead of the celery


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

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.


baked casserole

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: 6
Calories: 192kcal


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


  • 1-1/2 lbs yellow squash (fresh or frozen)
  • 2 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


  • 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.
    quartered squash in pot of water-2
  • Melt butter in a large 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.
    sauteed onion and celery-2
  • Add cooked squash to a 1.5-quart casserole dish that's been sprayed with non-stick spray. Add the cheese. Add sauteed onion and bell pepper mixture from step 3. Mix well. Taste test for flavor and add salt, if desired.
    casserole before baking
  • Bake uncovered for 30 minutes. Garnish with fresh parsley if desired.
    cooked casserole in glass dish with silver serving spoon


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.
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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