It’s the most wonderful time of the year. That is, butternut squash time obviously! With its rich, nutty flavor, our friend Mr. B is right at home in this cozy, healthy, and hearty Butternut Squash Casserole.
You can always find a butternut squash hanging out in my pantry. Many a fall weeknight, I default to my simple (though certainly not ho-hum), cinnamon Roasted Butternut Squash. It’s a good last-minute option for a holiday gathering as well.
When it’s time to prepare something Extra Super Special, however, this healthy butternut squash casserole will be a star.
It’s easy to prep in advance, making it a busy cook’s BFF.
The casserole filling boasts caramelized butternut squash, plus the addition of hearty kale to up its nutritional value and make it more dynamic.
Though this recipe is healthier than many sides, the addition of classic holiday standbys like nutmeg and thyme ensure this savory butternut squash casserole recipe feels right at home at a holiday gathering.
And since no proper casserole worthy of its name should be without a topping (and since it is the holiday season!), I knocked this one out of the park with a buttery sage Parmesan breadcrumb topping. It makes this casserole truly memorable.
How to Make Butternut Squash Casserole
You’ll feel like a superstar for eating comforting food that’s good for you too.
The robust filling is made with nutritious ingredients, and its flavor is alight with holiday flair.
The cheesy butternut squash casserole topping is salty, herby, savory, and crunchy.
(If you came to this recipe seeking a sweet, creamy butternut squash casserole versus the savory one we have here, definitely try this Healthy Sweet Potato Casserole instead.)
- Butternut Squash. A golden jewel of the winter season. Butternut squash is wonderfully sweet, nutty, and destined to be paired with other fall/winter flavors. Plus, with oodles of fiber and vitamin-A, it’s a healthy addition to any diet.
- Rosemary. Fresh rosemary adds hints of earthy notes.
- Kale. Packed with antioxidants and numerous vitamins, kale is an incredibly nutritious ingredient to sneak into this casserole. For the kale skeptics, sautéing it creates a tender and delicious texture.
- Breadcrumb Topping. Fresh breadcrumbs (or panko if you are in a hurry), Parmesan, sage, nutmeg, and butter make up our delicious topping. It’s toasty, cheesy, crispy goodness with delightful touches of cozy fall flavor.
If you’d like your butternut squash casserole with meat, try adding browned, crumbled sausage (or chicken sausage). Or keep the butternut squash casserole vegetarian as the recipe is written. It’s plenty satisfying!
- Sauté half of the squash, rosemary, and spices. I recommend sautéing in batches, so the outside of the butternut squash has room to caramelize.
- Add half of the kale, onions, garlic, and stock. Transfer mixture into a baking dish.
- Repeat these steps with the remaining half of the filling. Bake at 375 degrees F for 30 to 35 minutes.
- Stir the topping ingredients together. Sprinkle the breadcrumb mixture over the top of the casserole.
- Bake for 20 minutes more at 350 degrees F. ENJOY!
Serve a Pinot Noir or Zinfandel with this casserole. A Chardonnay would be a wonderful white wine option.
- To Store. Cover and refrigerate leftover casserole for up to 4 days.
- To Reheat. Rewarm leftovers in a baking dish in the oven at 350 degrees F.
- To Freeze. Freeze casserole in an airtight freezer-safe storage container for up to 3 months. Let thaw overnight in the refrigerator before reheating.
Make Ahead Tips
Chop the squash, thyme, garlic, kale, and onion up to 1 day in advance. Refrigerate each in a separate airtight storage container. Prepare the fresh breadcrumbs up to 1 day in advance, and store them in a container at room temperature.
Up to 1 day in advance, prepare the recipe through Step 6 (don’t bake it). Cover and refrigerate the dish until you’re ready to bake and finish it with the breadcrumb topping.
Toss in some chicken, turkey, or pork to turn the leftovers into a hearty main. Cooked sausage or shredded chicken would be delicious options (try one of my easy methods: Instant Pot Chicken, Crock Pot Shredded Chicken, Baked Chicken Breast, or How to Cook Shredded Chicken on the stovetop).
Recommended Tools to Make Butternut Squash Casserole
- Baking Dish. Perfect for making any of your favorite casseroles.
- Chef’s Knife. A sturdy, high-quality chef’s knife makes chopping much easier.
- Large Skillet. Great for sautéing vegetables and so much more.
Butternut Squash Casserole
For the Butternut Squash Filling:
- 2 tablespoons extra virgin olive oil divided
- 1 large (3 1/2 pound) butternut squash peeled, seeded, and diced into 3/4-inch cubes, divided (about 9 1/2 cups)
- 2 teaspoons minced fresh thyme divided (rosemary works as well)
- 2 cloves minced garlic divided (about 2 tablespoons)
- 1/2 teaspoon kosher salt divided
- 1/4 teaspoon black pepper divided
- 12 ounces kale* tough stems removed and chopped or torn into bite-sized pieces, divided (I used curly kale)
- 1 medium yellow onion thinly sliced, divided
- 1 cup low sodium vegetable stock or chicken stock divided
- Preheat the oven to 375 degrees F. Generously grease a shallow 9×13-inch casserole dish or similar 3-quart baking dish with non-stick cooking spray.
- Prepare the filling in two batches: Heat 1 tablespoon of the olive oil in a large, deep skillet or Dutch oven over medium heat. Add half of the butternut squash, ½ tablespoon of the rosemary, ¼ teaspoon salt, and 1/8 teaspoon pepper. Sauté until the squash is beginning to brown, about 3 minutes. The squash will still be too firm to eat.
- Next, add half of the kale, half of the onions, and half of the garlic. Cook until the kale and onions begin to soften, about 4 minutes.
- Add the 1/2 cup of the chicken stock, stir, and let cook 1 minute so that the stock reduces slightly.
- Transfer the mixture to the prepared baking dish and with a spoon, prod it into a relatively even layer.
- Heat the remaining tablespoon olive oil in the skillet, then repeat the above steps with the remaining half of each of the ingredients. Transfer the rest of the filling to the casserole dish. Cover the dish with aluminum foil and bake for 30 to 35 minutes or until the squash is soft when pierced with a sharp knife.
- While the squash bakes, prepare the topping: In a small bowl, combine the breadcrumbs, Parmesan, sage, nutmeg, and salt. Pour the melted butter over the top. Stir to combine.
- Remove the casserole from the oven, remove the foil, then sprinkle the top evenly with the breadcrumb mixture.
- Reduce the oven temperature to 350 degrees F, return the dish to the oven, then bake uncovered, until the bread crumbs are golden, about 20 minutes. Serve warm.
- *You also can omit the kale and make this recipe with a few extra cups of additional butternut squash, though we love the mix of both!
- **To make your own fresh breadcrumbs, tear bread (leftover sourdough or similar artisan breads or leftover baguette is my favorite; you can also use 3 slices of sandwich bread) into pieces and place in the food processor. Pulse in long bursts until you have crumbs. Measure and use in the recipe as directed.
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