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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.
    quartered squash in pot of water-2
  • 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.
    sauteed onion-bell pepper-celery
  • Add cooked squash and cheese to skillet. Mix well. Taste test for flavor and add salt, if desired.
    unbaked squash casserole
  • Bake uncovered for 30-35 minutes, or until slightly browned. Garnish with fresh parsley and extra cheese if desired.
    squash casserole in skillet


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.


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