I love this recipe because it balances sweet and savory flavors beautifully without feeling heavy. I get great texture from the roasted squash and apples, richness from the sausage and cheese, and depth from the fennel and herbs. I also like that it works well as a make-ahead side dish that still feels special.
Ingredients
(Note: All ingredient amounts are listed in the recipe card below.)
2 pounds butternut squash, peeled and cubed into medium-size chunks 2 Honeycrisp apples, peeled, cored and cubed into larger chunks (to match the squash) Olive oil Salt Black pepper 2 tablespoons pure maples syrup, divided use ½ teaspoon ground, dried sage 1 ½ teaspoons Herbes de Provence ½ 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 (fresh or fried), for garnish
Directions
I start by preheating my oven to 425° and lining a baking sheet with foil lightly misted with cooking spray. I place the cubed butternut squash and apples into a large bowl, drizzle them with olive oil, and season with salt, black pepper, 1 tablespoon of the maple syrup, dried sage, and Herbes de Provence. I toss everything well and spread it onto the baking sheet, then roast for about 35 minutes, stirring occasionally, until the squash is tender.
While the squash and apples roast, I heat a large skillet over medium-high heat with a drizzle of olive oil. I cook the crumbled sweet Italian sausage until browned and cooked through, then remove it to a bowl. If needed, I add a bit more oil to the pan and caramelize the fennel and onion together for about 10 to 12 minutes, until golden and jammy, then add them to the sausage.
Once the squash and apples are roasted, I switch the oven to broil. I combine the roasted squash and apples with the sausage, fennel, and onion mixture in a large bowl, add the remaining tablespoon of maple syrup, and toss everything together. I adjust the salt and pepper, then spoon the mixture into a medium-sized baking dish.
If I’m frying sage leaves, I heat oil in a small pan, fry the leaves briefly until crisp, and drain them on paper towels. To finish, I top the casserole with grated Gruyere cheese and place it under the broiler for a few minutes until melted and golden. I garnish with sage leaves and serve.
Servings and Timing
I make this casserole to serve 6 people. Prep time is about 20 minutes, cook time is roughly 45 minutes, and total time comes to around 1 hour and 5 minutes.
Variations
I sometimes swap the sweet Italian sausage for chicken sausage or turkey sausage for a lighter version. When I want it vegetarian, I skip the sausage and add sautéed mushrooms for depth. I also like experimenting with different cheeses, such as fontina or sharp white cheddar, depending on what I have on hand.
Storage/Reheating
I store leftovers in an airtight container in the refrigerator for up to 3 days. To reheat, I warm individual portions in the oven at 350° until heated through, or I use the microwave for convenience. I like reheating in the oven when possible to keep the texture from getting too soft.
FAQs
Can I make this casserole ahead of time?
I often prepare it a day ahead, stop before adding the cheese, and refrigerate it. When ready to serve, I add the cheese and broil.
What apples work best in this recipe?
I prefer Honeycrisp apples because they hold their shape and balance sweetness and tartness well.
Can I freeze this casserole?
I don’t recommend freezing it, as the squash and apples can become watery once thawed.
Is this casserole very sweet?
I find it lightly sweet, with the maple syrup enhancing the natural flavors without overpowering the savory elements.
Can I use pre-cut butternut squash?
I use pre-cut squash when I’m short on time, and it works just fine.
What can I substitute for Gruyere cheese?
I like fontina, Swiss, or even a mild provolone as substitutes.
Can I make this dish vegetarian?
I leave out the sausage and add mushrooms or extra fennel for a vegetarian version I really enjoy.
What size baking dish should I use?
I use a medium-sized baking dish, roughly 9 by 13 inches.
How do I keep the cheese from burning under the broiler?
I watch it closely and broil for just a few minutes until the cheese is melted and golden.
Can I serve this as a main dish?
I sometimes serve it as a light main with a salad, even though it’s traditionally a side.
Conclusion
This butternut squash casserole is one of my favorite fall side dishes because it’s comforting, flavorful, and perfect for gatherings. I love how it brings together seasonal ingredients in a way that feels both rustic and refined, and it always earns compliments at the table.
A comforting fall casserole made with roasted butternut squash and apples, savory Italian sausage, caramelized fennel and onion, and finished with melted Gruyere cheese for a dish that feels both rustic and elevated.
Ingredients
2 pounds butternut squash, peeled and cubed
2 Honeycrisp apples, peeled, cored, and cubed
2–3 tablespoons olive oil
Salt, to taste
Black pepper, to taste
2 tablespoons pure maple syrup, divided
½ teaspoon dried ground sage
1½ teaspoons Herbes de Provence
½ pound sweet Italian sausage, casings removed
2 small fennel bulbs, thinly sliced
1 onion, thinly sliced
1 cup grated Gruyere cheese
Fresh sage leaves, for garnish
Instructions
Preheat oven to 425°F and line a baking sheet with foil lightly misted with cooking spray.
In a large bowl, toss the butternut squash and apples with olive oil, salt, pepper, 1 tablespoon maple syrup, dried sage, and Herbes de Provence.
Spread evenly on the prepared baking sheet and roast for about 35 minutes, stirring occasionally, until squash is tender.
While roasting, heat a large skillet over medium-high heat with olive oil. Cook the sausage until browned and cooked through, then transfer to a bowl.
In the same skillet, add more oil if needed and cook fennel and onion for 10–12 minutes until caramelized. Add to the sausage.
Switch oven to broil. Combine roasted squash and apples with the sausage mixture and remaining maple syrup. Adjust seasoning with salt and pepper.
Spoon mixture into a medium baking dish and top with grated Gruyere.
Broil for a few minutes until cheese is melted and golden.
Garnish with fresh sage leaves and serve warm.
Notes
This dish can be assembled a day ahead; add cheese just before broiling.
Fontina or Swiss cheese can be substituted for Gruyere.
Chicken or turkey sausage works well as a lighter option.
Vegetarian version can be made by omitting sausage and adding mushrooms.
