Butternut Squash Casserole makes for a fantastic fall side dish, full of rich flavor. Plus get tips for preparing the squash!
This casserole recipe is creamy, crunchy, savory, and herby, with a little sweetness from the butternut squash. Serve it as part of a holiday dinner or anytime you want cozy fall flavors.
The Butternut Squash
For this dish, I like to make it easy on myself and buy the squash already cubed. Frozen butternut squash makes this dish so easy to prepare. If your grocery store carries freshly cubed butternut squash, that also works as a helpful shortcut.
If either of those options isn’t available, and you’re not confident in peeling and cutting a fresh butternut squash, try microwaving it first.
Using a sharp knife, poke a few shallow slits into the squash. Place a few paper towels on the bottom of your microwave carousel and then place the squash on top of the paper towels. Microwave on high for five minutes, remove it from the microwave, let it sit until it’s cool enough to handle. The squash should be just soft enough to more easily peel and cut, but not cooked through.
The squash is tossed with melted butter, salt, and pepper before it’s roasted.
The sauce for this casserole is basically a béchamel sauce, which is a basic white sauce made with butter, flour, and milk. This one also has some onion, salt, garlic powder, and a bit of nutmeg. The sauce is poured over the roasted squash before a final round of baking.
Before you bake the squash with the sauce, you add a crunchy coating made of Permesan cheese, panko breadcrumbs, finely chopped fresh sage leaves, and a bit of melted butter that coats each crumb and helps it to brown.
Tip: If you don’t have fresh sage, 1 tablespoon of dried, rubbed sage can be used in its place.
Ground sage isn’t recommended for this recipe, as it can be overpowering, so if you’re not able to find fresh sage or dried rubbed sage, this ingredient can be skipped.
Although this recipe has a few components to it, everything can be prepared while the squash is in the oven baking.
To make the casserole, first preheat your oven to 450°F.
In a large casserole dish, add the cubed butternut squash, 2 tablespoons of the melted butter, ½ teaspoon of the salt, and the pepper. Stir this together directly in the baking dish and then bake for 25 minutes or until the squash is tender.
While the squash is baking, make the topping and the sauce.
In a medium bowl, stir together the Parmesan cheese, breadcrumbs, sage, and 1 tablespoon of the butter until well combined. Set this aside until it’s ready to be added to the squash.
In a medium saucepan add the remaining 3 tablespoons of butter, the remaining ½ teaspoon of salt, and the onion. Cook this over medium heat, occasionally stirring, until the onion is soft. This will take about 3 minutes.
Stir in flour and cook this for about 30 seconds, stirring constantly. Slowly stir in the milk, then stir in the garlic powder and nutmeg. Continue stirring until any lumps of flour have disappeared and the mixture is thick enough to coat the back of a spoon; this usually happens just before the mixture is about to come to a boil. Keep this warm until the squash is ready to come out of the oven.
When the squash is tender, remove the dish from the oven and then pour the sauce evenly over the squash. Sprinkle the breadcrumb mixture evenly over the sauce and then return the baking dish to the oven. Bake this for 10 minutes more or until the breadcrumbs are browned.
Remove the baking dish from the oven. Let stand 10 minutes before serving.
Serving The Casserole
This makes a fantastic side dish for Thanksgiving! (Maybe you need a break from Sweet Potato Casserole this year.) Because there are so many dishes at the holiday table, this recipe will likely work well for 8 or even 10 servings.
As a side dish for a regular dinner, this recipe will serve 6 people. Try serving alongside roast chicken and a fresh salad.
More Butternut Squash Recipes
If you love butternut squash, you’ve gotta check out my other butternut squash recipes. I have an article detailing nine ways to cook butternut squash, and then more details on how to roast it whole, how to microwave it, how to cook it in the Instant Pot, how to roast cubes of squash, and then some truly delicious butternut squash recipes:
- Mashed Butternut Squash
- Butternut Squash Pasta Sauce
- Roasted Butternut Squash with Cranberry Sauce
- Sheet Pan Dinner made with Butternut Squash, Gnocchi and Brown Butter
- Butternut Squash Soup with Coconut Milk
Fresh butternut squash can be used in place of the frozen. Look for it already cubed in your produce section or see the tips in post above to make it easier to cut.
Listen to me explain briefly about how to make this casserole, with some great tips along the way, by clicking the play button below:
- 2 (15 oz.) bags cubed frozen butternut squash, thawed
- 6 Tbsp. butter, melted, divided
- 1 tsp. salt, divided
- ¼ tsp. ground black pepper
- 1 cup grated Parmesan cheese
- 1 cup panko breadcrumbs
- 2 Tbsp. fresh finely chopped sage leaves
- ½ large onion, finely diced
- 3 Tbsp. all-purpose flour
- 1 and ½ cup whole milk
- ½ tsp. granulated garlic
- ¼ tsp. grated nutmeg
- Preheat oven to 450°F.
- In a large baking dish add the butternut squash, 2 tablespoons of the melted butter, ½ teaspoon of the salt, and the pepper. Stir to combine.
- Place dish in oven. Bake 25 minutes or until squash is tender.
- Meanwhile in a medium bowl stir together Parmesan, panko breadcrumbs, sage, and 1 tablespoon of the butter until well combined. Set aside.
- In a medium saucepan add remaining 3 tablespoons of butter, remaining ½ teaspoon of salt, and onion. Cook over medium heat, stirring occasionally, until onion is soft, about 3 minutes. Stir in flour. Cook 30 seconds, stirring constantly.
- Slowly stir in milk. Stir in garlic powder and nutmeg. Continue stirring until no lumps of flour remain and mixture is thick enough to coat the back of a spoon. Keep warm until squash is cooked.
- Remove baking dish from oven. Pour sauce evenly over butternut squash. Top with breadcrumb mixture.
- Return baking dish to oven. Bake 10 minutes more or until breadcrumbs are browned.
- Remove baking dish from oven. Let stand 10 minutes before serving.