This butternut squash casserole takes casseroles to the next level. Topped with cheese and crispy breadcrumbs, each mouthful boasts a rich flavor and contrasting textures.
Let’s talk about cozy and comforting casseroles using seasonal produce.
I love Fall because it means we have an abundance of pumpkins and squash. While 99% of our recipes are for the sweeter things, I actually prefer to use them in more savory dishes.
When roasted, butternut squash caramelizes and yields the most tender and sweet vegetable. While delicious on its own, we elevate it by making it the star ingredient in our easy butternut squash casserole recipe.
Table of Contents
Why this recipe works
- Can be served as a main dish or side dish. Like a zucchini casserole, the beauty of this dish is that it works as both a side dish or the main course it itself. Of course, it’s a must-make for the holiday season!
- Easy to make ahead. I like to prep this casserole over the weekend and keep it in the fridge for the week ahead. It keeps really well, and it makes dinnertime a breeze.
- Full of textures and flavor. You get the tenderness of the squash, the melty cheese, the creaminess in the sauce, and the crispy breadcrumbs. It’s slightly sweet and savory, and let’s be real; no one can resist something with cheese.
This squash casserole recipe is very simple and uses everyday ingredients that you probably have in your kitchen at all times. Here’s everything you’ll need:
- Butternut squash. Chopped into bite-sized pieces. Discard any seeds or sinew, and be sure to remove the skin.
- Onion and garlic. Aromatics that are essential for flavor.
- Spinach. I prefer using frozen spinach and thawing it for convenience, but if you’d prefer to use fresh spinach, opt for the English variety.
- Heavy cream. To mix with the spinach and creates a rich and creamy sauce, and also helps to bind the filling together.
- Cheese. I used parmesan and gruyere, but use any full-flavored cheese you like.
- Breadcrumbs. To create a golden crispy topping. I prefer using panko breadcrumbs, but the standard kind works just fine.
- Salt and pepper. To taste.
- Butter. To grease the baking dish and cook the onion.
- Olive oil. To roast the squash beforehand.
- Fresh thyme. To serve.
How to make a butternut squash casserole
The secret to the creamy texture of this squash casserole is roasting the butternut first. For such an impressive looking dish, you’ll love how foolproof it is to make.
Roast the butternut squash: Start by cutting the butternut squash into cubes. In a mixing bowl, mix the squash cubes with olive oil, salt, and pepper. Transfer onto a large baking sheet and roast for 25 minutes until tender. Remove the squash from the oven and set it aside.
Make the casserole base: Add a tablespoon of butter to a non-stick pan and place it over medium heat, then add the onions and cook for 5 minutes before adding the garlic.
Now, drain the defrosted spinach to get rid of the excess liquid. Add the spinach to the pan and cook with onion and garlic for a few minutes. Start adding the heavy cream one tablespoon at a time and cook for 5 minutes until the sauce thickens. Once that is done, fold through the roasted squash.
Prepare the breadcrumb topping: Combine the breadcrumbs with room-temperature butter in a small bowl and whisk well.
Assemble: Transfer the butternut squash mixture into the baking dish. Sprinkle with grated gruyere and parmesan cheese. Give the casserole a light stir and add the breadcrumb topping.
Bake: Finally, bake the squash casserole for 10 to 15 minutes, or until the cheese is bubbling and the breadcrumbs are golden brown.
Recipe tips and variations
- Cut the butternut squash into even pieces so that they bake evenly. This ensures that the squash casserole is soft and tender throughout.
- Although slightly more time consuming, shred the cheese by hand instead of using the pre-shredded kind. Not only does it melt better, but it also doesn’t clump up.
- Use a large baking dish (at least 9 x 13 inches) to ensure everything cooks evenly and completely. Butternut squash also releases extra liquid once baked, so baking it in a more shallow container helps this dish’s overall flavor and texture.
- Add bacon or finely chopped pancetta to the casserole to add extra protein and a punch of flavor. This is actually a common addition because *some* family members can’t appreciate a meatless meal.
- Use a mix of spices to change up the flavor, like cinnamon, cumin, and nutmeg. I love to add some heat, either in the form of red pepper flakes or cayenne pepper.
If I’m serving this casserole as a main dish, I tend to keep the sides on the heartier side to compensate. Mashed potatoes, roasted root vegetables, and mac and cheese are all solid options.
To store: Store leftovers in an airtight container in the fridge. The casserole will be good for 3 to 5 days.
To freeze: Place portions of the casserole in a shallow container and store it in the freezer for up to 6 months.
To Reheat: The best way to reheat a casserole is by using the oven. Put the casserole leftovers into an oven-safe dish and reheat for 15-20 minutes covered with foil. Remove the foil and bake for a few more minutes to get the top crispy. You can also micrwave it if you are in a pinch.
More casserole recipes to try
- Chicken casserole
- Cheeseburger casserole
- Green bean casserole
- Pizza casserole
- Taco casserole
- Tuna casserole
- French onion chicken casserole
- Spaghetti squash casserole
Frequently asked questions
Pre-cook the butternut squash to prevent the casserole from getting watery. If you are using spinach, use frozen, thawed, and squeeze-dried spinach instead of fresh spinach. The latter releases a lot of water when cooked and can make the casserole soggy.
You can roast the butternut squash, assemble the casserole, and freeze it to bake later. Cover the casserole with food wrap and aluminum foil and freeze it for up to two weeks.
Butternut Squash Casserole
- 2 medium butternut squash peeled and chopped
- 2 tablespoons olive oil
- 1/2 teaspoon salt
- 1/2 teaspoon pepper
- 1/4 cup butter divided
- 2 large onions sliced
- 3 cloves garlic minced
- 18 ounces frozen spinach thawed and drained
- 1 cup gruyere cheese grated
- 1 cup parmesan cheese grated
- 3/4 cup heavy cream
- 1 1/2 cups panko breadcrumbs
- Preheat the oven to 200C/400F. Lightly grease a 9 x 13-inch baking dish and set aside.
- In a mixing bowl, add the cubed butternut squash, olive oil, salt and pepper. Mix until fully combined.
- Transfer onto a large baking sheet and roast for 25 minutes, until tender. Remove from the oven and set aside.
- Thaw the spinach then drain all excess liquid.
- Heat 1 tablespoon of the butter in a large non-stick pan and place it over medium heat. Once hot, add the onion and cook for 5-6 minutes, until tender. Add the garlic and cook for a further minute.
- Reduce the heat and add the thawed spinach. Cook for several minutes, before adding the heavy cream one tablespoon at a time. Stir and cook for 5 minutes, until it has thickened. Add the cooked butternut squash and gently mix until combined.
- In a small bowl, whisk together 3 tablespoons of the butter with the panko bread crumbs.
- Transfer everything into the baking dish. Sprinkle with the gruyere cheese and parmesan cheese. Mix until gently incorporated. Sprinkle bread crumbs on top.
- Bake for 10-15 minutes, until the cheese is bubbling and melted.
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