Butternut Squash Casserole

Butternut Squash Casserole brings together everything I love about autumn cooking: vibrant colors, earthy flavors, and that perfect balance between sweet and savory that makes fall food so special. This has become my signature dish for family gatherings.

Every October, when the leaves start turning those gorgeous shades of amber and gold, I think about the harvest dinners at Grandma’s farm. She’d roast butternut squash until the edges caramelized, filling the kitchen with the most incredible sweet, nutty aroma. Those evenings taught me that the best fall recipes celebrate the season’s bounty without overcomplicating things. This butternut squash casserole captures that spirit perfectly. Tender cubes of roasted squash and sweet Honeycrisp apples mingle with savory Italian sausage and caramelized fennel, all topped with melted Gruyere that gets beautifully golden under the broiler. The maple syrup adds just a whisper of sweetness that ties everything together, while the Herbes de Provence bring that aromatic, slightly floral quality that makes each bite feel special. I’ve served this at Thanksgiving, brought it to potlucks, and made it countless times for regular Tuesday dinners when we just need something warming and delicious. Your kitchen’s about to smell incredible.

The Secret Behind This Fall Casserole

Growing up in a Midwest kitchen where seasonal cooking wasn’t just a trend but a way of life, I learned that the best autumn dishes honor both the sweet and savory elements that make this season so special. This warming butternut squash casserole embodies that philosophy, bringing together unexpected ingredients that work in beautiful harmony.

• Roasted butternut squash and apples develop deep, caramelized flavors that sweet potatoes simply can’t match, creating layers of complexity in every bite
• The combination of sweet Italian sausage with caramelized fennel and onions provides savory balance that prevents the dish from being one-dimensional
• Serves equally well as a main course for vegetarian guests (simply omit the sausage) or as an impressive holiday side dish
• Gruyere cheese adds nutty richness without overwhelming the delicate squash flavor, melting into golden perfection under the broiler
• Everything comes together in about an hour, making this butternut squash casserole achievable even on busy weeknights
• The gluten-free nature makes it an excellent alternative to traditional bread-based stuffing at holiday meals

The Building Blocks

Butternut squash forms the sweet, creamy foundation of this casserole, and roasting it brings out natural sugars that caramelize beautifully. I always choose pre-cubed squash from the grocery store when I’m short on time, though cutting your own from a whole squash offers the freshest flavor.

Honeycrisp apples contribute tart-sweet balance and hold their shape during roasting, unlike softer varieties that turn to mush. In my kitchen, I prefer Honeycrisp, Golden Delicious, or Gala for their ability to maintain texture while developing concentrated apple flavor.

Sweet Italian sausage provides savory, fennel-spiced richness that complements the sweet elements without overpowering them. Betty’s tip: Remove the casings before cooking so the meat crumbles into bite-sized pieces throughout the casserole.

Fennel bulbs transform during caramelization, losing their strong licorice flavor and becoming sweet, jammy, and absolutely delicious. I’ve found that many people who claim to dislike fennel love it in this butternut squash casserole because the cooking method completely changes its character.

Pure maple syrup adds subtle sweetness that enhances both the squash and apples without making the dish taste like dessert, and using real maple syrup rather than pancake syrup makes a noticeable difference.

Herbes de Provence brings aromatic complexity with its blend of thyme, rosemary, lavender, and other Mediterranean herbs that make this casserole feel elevated and special.

Gruyere cheese melts into nutty, slightly sweet pools of golden deliciousness that complement the butternut squash perfectly. Through trial and error, I learned that Gruyere’s flavor profile works better here than sharper cheddars or milder mozzarella.

Sage (fresh or fried) provides the finishing touch that makes this butternut squash casserole unmistakably autumnal, adding earthy, slightly peppery notes that tie all the flavors together.

From Start to Finish

Step 1. Betty always starts by preheating the oven to 425°F and lining a baking sheet with foil lightly misted with cooking spray, which prevents sticking and makes cleanup effortless.

Step 2. I’ve found that tossing the cubed butternut squash and apples with oil, seasonings, maple syrup, and herbs in a large bowl ensures every piece gets evenly coated before roasting.

Step 3. After spreading the mixture on the baking sheet, roast for about 35 minutes, stirring occasionally. This step develops those caramelized edges that make this butternut squash casserole so irresistible.

Step 4. While the squash roasts, brown the crumbled sausage in a hot skillet until cooked through, then remove and set aside, which allows you to use the flavorful drippings for caramelizing the vegetables.

Step 5. The key I discovered is caramelizing the sliced fennel and onion together for 10-12 minutes until deeply golden and jammy, which creates sweet, complex flavors that enhance the entire dish.

Step 6. Through trial and error, I learned to switch the oven to broil mode before assembling the casserole, ensuring it’s at the perfect temperature for melting and browning the cheese topping.

Step 7. My family prefers when I combine all the roasted and caramelized components with the remaining tablespoon of maple syrup, then taste and adjust the salt-pepper balance to create that perfect sweet-savory harmony.

Step 8. After spooning everything into a baking dish and topping with grated Gruyere, just a few minutes under the broiler creates that gorgeous golden-brown cheese crust that makes this butternut squash casserole truly special.

Keeping This Casserole Fresh

I typically store leftover butternut squash casserole in airtight containers in the refrigerator for up to 4 days, and while the texture changes slightly as the moisture redistributes, the flavors actually deepen and meld beautifully overnight. This makes it excellent for make-ahead holiday planning.

Betty’s approach to freezing this casserole involves careful consideration of texture. While the flavors freeze well, the water content in butternut squash and apples can create a slightly mealy texture upon thawing. If you do freeze it, I recommend doing so before baking, wrapping it tightly, and using within 2 months.

For the best texture when reheating, I warm the casserole in a covered dish at 350°F for about 20-25 minutes until heated through, then uncover and broil briefly to re-crisp the cheese topping. Individual portions reheat well in the microwave, though you’ll lose some of that crispy-topped texture we love.

Perfect Partners for Butternut Squash Casserole

• Christmas Salad Recipe cuts through the richness of the casserole with tart, fresh flavors and crisp textures
• Roasted Butternut Squash Soup makes this butternut squash casserole the perfect Thanksgiving side dish, with flavors that complement traditional holiday proteins beautifully
• Fall Dinner Recipes adds nutty, earthy notes and chewy texture that pair wonderfully with the tender roasted vegetables
• Maple Glazed Chicken creates a complete autumn dinner when served alongside this warming, colorful casserole
• Easy Vegetable Soup Recipe provides something to soak up all those delicious maple-glazed juices that pool in the bottom of the baking dish

FAQs

Butternut Squash Casserole

Warming butternut squash casserole with roasted squash, sweet apples, Italian sausage, caramelized fennel and onions, topped with melted Gruyere cheese.

Print Recipe Pin Recipe

Prep Time 20 minutes mins

Cook Time 45 minutes mins

Total Time 1 hour hr 5 minutes mins

Servings: 6 portions

Course: Dinner, Main Course, Side Dish

Cuisine: American

Calories: 288

Ingredients Equipment Method Notes

Ingredients

  

• 2 pounds butternut squash peeled and cubed into medium-size chunks
• 2 Honeycrisp apples peeled, cored and cubed into larger chunks
• 2 tablespoons olive oil
• Salt and black pepper to taste
• 2 tablespoons pure maple syrup divided use
• 0.5 teaspoon ground dried sage
• 1.5 teaspoons Herbes de Provence
• 0.5 pound sweet Italian sausage casings removed and crumbled
• 2 small fennel bulbs stalks/fronds removed, cut in half lengthwise, cored, and thinly sliced
• 1 onion quartered and thinly sliced
• 1 cup grated Gruyere cheese
• Fresh sage leaves for garnish

Equipment

• baking sheet
• large bowl
• large skillet
• Medium baking dish (9×13)

Method

 

1. Preheat your oven to 425°F and line a baking sheet with foil lightly misted with cooking spray.
2. Place cubed butternut squash and apples into a large bowl. Drizzle in about 2 tablespoons of oil. Sprinkle over salt and black pepper, along with 1 tablespoon of the maple syrup, the dried sage and the Herbes de Provence. Toss to coat.
3. Turn the mixture out onto your prepared baking sheet and roast for about 35 minutes, stirring occasionally for even roasting, or until the squash is tender.
4. While the butternut squash and apples roast, place a large skillet over medium-high heat and add a small drizzle of olive oil. Once the pan is very hot, add the crumbled sweet Italian sausage and cook until browned and cooked through, a few minutes. Remove from the pan and keep in a bowl.
5. If additional oil is needed in the pan, add a small amount. Then add the sliced fennel and onion into the pan and caramelize together for about 10-12 minutes, or until deeply golden and a bit jammy in texture. Remove from pan and add to the sausage.
6. Once the butternut squash and apples are tender and roasted, switch your oven setting to broil.
7. To prepare the casserole, carefully spoon the roasted butternut squash and apples into a large bowl and add the sausage, fennel and onion mixture. Pour in the remaining 1 tablespoon maple syrup and toss to combine (add a touch more salt and pepper to create a sweet-savory flavor). Spoon into a medium size baking dish.
8. If preparing fried sage leaves as a garnish, heat about 1/4 cup of oil in a small sauce pan or pot. Once shimmering, add the sage leaves and fry for about 20 seconds, then remove and drain on paper towels. Sprinkle lightly with salt and set aside.
9. To finish the casserole, top with the grated Gruyere cheese and place into the oven under the broiler for a few minutes, until the cheese is melted and golden-brown. Garnish with sage leaves and serve.

Notes

Pre-cut butternut squash can be used for convenience. For vegetarian option, simply omit the sweet Italian sausage. Can substitute mozzarella, white cheddar, Jack cheese, or crumbled brie for Gruyere. Make ahead by assembling without cheese, refrigerating, then bringing to room temp before topping with cheese and baking at 350°F for 25-30 minutes.