This low-carb squash casserole is the ultimate comfort food made lighter! With tender squash, a creamy, cheesy base, and a perfectly golden topping, it’s the kind of dish that brings everyone back for seconds.
We first fell in love with this recipe during a busy week when we craved something hearty yet nourishing. It’s become a family favorite, especially during summer and fall when squash is in season.
Whether you’re looking for an easy weeknight dinner or a crowd-pleasing side for a holiday table, this casserole checks all the boxes.
Quick Look at What’s Inside
Nutrition Benefits of Low-Carb Squash Casserole
This dish isn’t just delicious, it’s packed with nutrients that support your overall well-being. Here’s why we love it:
- Squash is a powerhouse of vitamins and minerals: Yellow squash and zucchini are rich in vitamin C, potassium, and antioxidants, which help maintain a healthy immune system and heart.
- Low in carbs, high in fiber: This casserole is perfect for those following a low-carb or keto lifestyle. The fiber in squash helps with digestion and keeps you feeling full longer.
- Protein-packed goodness: The addition of cheese and optional chicken or ground beef boosts the protein content, helping to keep you energized throughout the day.
- Calcium-rich for healthy bones: The cheesy topping isn’t just for flavor—it also provides a great dose of calcium to support bone health.
Ingredients for Low-Carb Squash Casserole
To make this delightful casserole, you’ll need:
- 4 medium yellow squash or zucchini, thinly sliced
- 1 small yellow onion, diced
- 1 cup shredded cheddar cheese (plus extra for topping)
- ½ cup grated Parmesan cheese
- ½ cup sour cream
- ¼ cup mayonnaise
- 2 large eggs, lightly beaten
- 1 teaspoon garlic powder
- 1 teaspoon onion powder
- ½ teaspoon smoked paprika (optional, for smoky flavor)
- Salt and pepper, to taste
- ½ cup almond flour (for topping)
- 2 tablespoons butter, melted
Optional:
- 1 cup cooked, shredded chicken or ground beef for added protein
You’ll also need a 9×13-inch baking dish and a sharp knife or mandoline for slicing.
How to Make Low-Carb Squash Casserole
This recipe is as simple as it is satisfying. Here’s how to make it:
1. Preheat the oven
Set your oven to 375°F and grease your baking dish lightly with cooking spray or butter.
2. Prepare the squash
Thinly slice the squash (and zucchini, if using) into rounds about 1/4 inch thick. Spread the slices evenly in the baking dish and sprinkle with a pinch of salt to draw out excess moisture.
3. Sauté the onion
Heat a small skillet over medium heat and sauté the diced onion until it’s soft and translucent, about 3–4 minutes. Spread the cooked onion over the squash.
4. Mix the creamy filling
In a large bowl, whisk together the sour cream, mayonnaise, eggs, cheddar cheese, Parmesan cheese, garlic powder, onion powder, smoked paprika, and a pinch of salt and pepper. If adding chicken or ground beef, stir it in at this stage.
5. Assemble the casserole
Pour the creamy mixture evenly over the squash and onions, ensuring everything is coated.
6. Add the topping
In a small bowl, mix the almond flour with melted butter. Sprinkle this mixture over the casserole, then top with a little extra shredded cheddar for that irresistible cheesy crust.
7. Bake to perfection
Place the casserole in the oven and bake for 35–40 minutes, or until the topping is golden brown and the filling is bubbling. Let it cool for 5–10 minutes before serving.
Tips for the Best Low-Carb Squash Casserole
- Drain excess moisture Squash contains a lot of water, so salting the slices before baking helps prevent a soggy casserole. You can also pat the slices dry with a paper towel.
- For added flavor, use a mix of cheeses While cheddar is classic, mixing in mozzarella, Gruyere, or Monterey Jack can elevate the flavor.
- Make it your own Swap yellow squash for zucchini, use ground turkey instead of beef, or try adding fresh herbs like thyme or parsley for a burst of freshness.
- Looking for a vegetarian option? Skip the meat and add sautéed mushrooms or spinach for a veggie-packed twist.
Variations, Leftovers & Storage
This casserole is versatile and reheats beautifully, making it perfect for meal prep.
- Ingredient swaps: Use acorn squash for a fall-inspired flavor, or try subbing Greek yogurt for sour cream to lighten it up.
- Leftovers: Store any leftovers in an airtight container in the fridge for up to 3 days. Reheat in the oven at 350°F until warmed through.
- Freezing tip: If you plan to freeze, assemble the casserole without baking. Wrap tightly and freeze for up to 2 months. Thaw overnight in the fridge and bake as directed.
Nutrition Facts
Here’s a breakdown of the estimated nutrition per serving (based on 6 servings):
- Calories: 280
- Protein: 12g
- Fat: 22g
- Carbohydrates: 6g
- Fiber: 2g
- Net Carbs: 4g
These values may vary slightly depending on the ingredients you use, but rest assured this recipe is a low-carb winner!
Frequently Asked Questions
Can I use frozen squash for this recipe?
Yes, but be sure to thaw and drain it thoroughly to remove excess water.
Can I make this casserole ahead of time?
Absolutely! Assemble the casserole, cover it tightly, and refrigerate for up to 24 hours before baking.
What can I use instead of almond flour?
Crushed keto crackers, or grated Parmesan are great low-carb alternatives.
Is this recipe keto-friendly?
Yes, it’s perfect for keto! With just 4g net carbs per serving, it fits well into a low-carb or ketogenic diet.
Can I add more vegetables?
Of course! Bell peppers, mushrooms, or spinach would all be delicious additions.
A cozy casserole made simple and guilt-free!
We hope you love this effortless low-carb squash casserole as much as we do. It’s hearty, healthy, and so easy to make it’s sure to become a staple in your kitchen.
If you try this recipe, let us know in the comments below. Snap a photo and tag us on Instagram or Pinterest, nothing makes us happier than seeing your creations!
Looking for more low-carb inspiration? Check out our recipes for keto acorn squash bowls, shredded squash casserole, or our chicken and squash bake!
Low-Carb Squash Casserole
Ingredients
- 4 medium yellow squash or zucchini thinly sliced
- 1 small yellow onion diced
- 1 cup shredded cheddar cheese plus extra for topping
- ½ cup grated Parmesan cheese
- ½ cup sour cream
- ¼ cup mayonnaise
- 2 large eggs lightly beaten
- 1 teaspoon garlic powder
- 1 teaspoon onion powder
- ½ teaspoon smoked paprika optional, for smoky flavor
- Salt and pepper to taste
- ½ cup almond flour for topping
- 2 tablespoons butter melted
Optional:
- 1 cup cooked shredded chicken or ground beef for added protein
Instructions
Preheat the oven
- Set your oven to 375°F and grease your baking dish lightly with cooking spray or butter.
Prepare the squash
- Thinly slice the squash (and zucchini, if using) into rounds about 1/4 inch thick. Spread the slices evenly in the baking dish and sprinkle with a pinch of salt to draw out excess moisture.
Sauté the onion
- Heat a small skillet over medium heat and sauté the diced onion until it’s soft and translucent, about 3–4 minutes. Spread the cooked onion over the squash.
Mix the creamy filling
- In a large bowl, whisk together the sour cream, mayonnaise, eggs, cheddar cheese, Parmesan cheese, garlic powder, onion powder, smoked paprika, and a pinch of salt and pepper. If adding chicken or ground beef, stir it in at this stage.
Assemble the casserole
- Pour the creamy mixture evenly over the squash and onions, ensuring everything is coated.
Add the topping
- In a small bowl, mix the almond flour with melted butter. Sprinkle this mixture over the casserole, then top with a little extra shredded cheddar for that irresistible cheesy crust.
Bake to perfection
- Place the casserole in the oven and bake for 35–40 minutes, or until the topping is golden brown and the filling is bubbling. Let it cool for 5–10 minutes before serving.