Easy keto squash casserole recipe that uses fresh or frozen yellow squash! Made with cheddar cheese, mayonnaise, butter, onion, bell pepper, and celery and baked till golden brown. A delicious and simple recipe for any time of the year!
Why This Recipe Works
No topping needed - here in the south, most southern squash casseroles are topped with some sort of cracker topping which isn't low carb or keto-friendly. Luckily, this casserole doesn't need a topping (not even a pork rind topping!). It's perfect as-is!
Rich and creamy - its creamy and cheesy texture will make you want seconds! It's a Southern side dish favorite and a great choice for most main dishes.
Easy prep - 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.
Great side dish any time of the year - While it's perfect for the holidays, like Thanksgiving and Christmas, it's an easy and delicious year-round side dish.
Low carb, keto, gluten-free, grain-free, and sugar-free!
Ingredients for Keto Squash Casserole
please refer to the recipe card for detailed ingredients and helpful information
- Fresh Yellow Squash - or frozen if that's all you can find. Or use zucchini.
- Seasoning Blend - frozen chopped onion, bell pepper, and celery blend - so handy!
- Cheddar Cheese - use pepper jack if you want to add a litle kick.
- Butter - or use ghee.
- Keto Mayonnaise - such as Primal Kitchen Avocado Oil Mayonnaise.
- Seasonings - salt, pepper, garlic powder (or use poultry seasoning for a surprisingly nice flavor!).
- Optional - use a can of Rotel tomatoes for some added heat. Just be sure to thoroughly drain the tomatoes!
How to Make Keto Squash Casserole
please refer to the recipe card for detailed directions.
(1) Boil the chopped squash, then drain.
(2) In an oven-proof skillet, saute the onion, bell pepper, and celery in butter or ghee.
(3) Add the squash, keto-friendly mayo, cheese, and seasonings. Stir.
(4) Bake as directed.
Frequently Asked Questions
Here in the south, fresh yellow squash, or summer squash, is available at any time of the year. However, frozen squash is a good substitute. Boil or microwave the frozen squash per the package directions. 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.
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.
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 lids. Available now on Amazon.
Other Side Dishes
This recipe was originally published in 2020 and was updated in 2021.
If you try this delicious squash recipe, please let me know in the comments below.
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Easy Keto Squash Casserole
- Sharp kitchen knife
- Cutting board
- large pot
- measuring spoons
- measuring cup
- Casserole dish or skillet
- 1-½ lbs yellow squash (fresh or frozen)
- 1 tablespoon salted butter
- ½ cup frozen chopped onion, bell pepper, and celery mixture
- ¼ cup full fat mayonnaise
- ¼ teaspoon garlic powder
- ½ teaspoon salt (test flavor before baking, add salt if needed)
- ⅛ teaspoon 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.
- 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, salt, 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.