Butternut Squash Casserole is the dish I turn to every fall when I crave something that’s both heartwarming and impressive enough to steal the show at any table. Imagine cubes of caramelized squash and juicy apples, mingled with fragrant herbs, golden onions, sweet fennel, crumbled sausage, and crowned with a bubbling layer of Gruyere cheese, all tied together with a touch of maple syrup. The flavors are an irresistible harmony of sweet, savory, earthy, and herbal notes. If you’re ready to create a Butternut Squash Casserole that’ll become an instant favorite in your home, you’ve got to try this recipe.

Ingredients You’ll Need

Butternut Squash Casserole Recipe - Recipe Image

Ingredients You’ll Need

The charm of this Butternut Squash Casserole is that it’s built on a handful of everyday ingredients, each adding their own voice to the chorus of flavors. Nothing fancy here, but every component—from the sweet squash and apples to the aromatic sausage and Gruyere—plays a vital role in the final result.

Butternut squash: The star of the show, it brings velvety sweetness and bright color to the casserole.

Honeycrisp apples: Their crispness and juicy tart-sweet flavor balance the richness of the dish.
Olive oil: Coats the veggies and fruit for roasting, giving a subtle fruity richness.

Salt: Essential for bringing out the natural sweetness and enhancing every bite.
Black pepper: Adds a gentle kick of heat and earthiness.

Pure maple syrup: A little drizzle ties all the flavors together with rich sweetness. Use good quality syrup for the best depth.
Ground sage: Dried sage introduces a warm, savory note perfect for squash and sausage dishes.
Herbes de Provence: This French herb blend creates a bold, aromatic foundation—don’t skip it!

Sweet Italian sausage: Savory and lightly spiced, it adds heartiness and flavor complexity.
Fennel bulbs: Fennel brings a mild licorice sweetness, turning jammy and golden when caramelized.
Onion: Softened and caramelized, onion adds depth and a hint of sweetness.

Gruyere cheese: Gruyere melts like a dream and infuses a nutty, creamy richness you’ll adore.
Fresh sage leaves: Use as a garnish—either fresh for a pop of herbal freshness, or fried for a shatteringly crisp finish.

How to Make Butternut Squash Casserole

Step 1: Roast the Squash and Apples

Your Butternut Squash Casserole adventure starts with roasting. Preheat the oven to 425°F and line a baking sheet with foil that’s been misted with cooking spray. Toss the cubed squash and apple pieces in olive oil, salt, pepper, one tablespoon of maple syrup, plus the sage and Herbes de Provence. Spread everything evenly on your baking sheet and roast for about 35 minutes, giving it a gentle stir now and then until the squash goes fork-tender and caramelized. This step is where you’ll coax out every ounce of natural sweetness and flavor—don’t rush it!

Step 2: Brown the Sausage

While your kitchen fills with the scent of roasting veggies, heat a large skillet (cast-iron is perfection here) over medium-high and splash in a little olive oil. Add the crumbled sweet Italian sausage and cook until browned and cooked through. Scoop it out into a bowl so it stays juicy and ready to join the party later.

Step 3: Caramelize Fennel and Onion

Don’t wipe that skillet just yet! If you need a touch more oil, add it now, then tumble in the thinly sliced fennel and onion. You’ll want to cook these low and slow, letting them caramelize and soften for about 10–12 minutes. By the end, you’ll have a tangle of golden, jammy deliciousness to layer extra flavor into your Butternut Squash Casserole.

Step 4: Combine and Assemble

Once the squash and apples are perfectly roasted, switch your oven to “broil.” Gently scoop the roasted squash and apples into a large mixing bowl, then add the cooked sausage, caramelized fennel, and onion. Pour over the remaining tablespoon of maple syrup, sprinkle in an extra bit of salt and pepper if you like a more pronounced flavor contrast, and toss it all so every component is mingling together. Transfer into a 9 by 13-inch baking dish, ready for its cheesy crown.

Step 5: Fry Sage Leaves (Optional but Magical)

If you want to take this Butternut Squash Casserole over the top, quickly fry some sage leaves. Heat a quarter cup of oil in a saucepan, get it shimmering hot, then fry sage leaves for about 20 seconds. Drain them on paper towels and give them the tiniest sprinkle of salt—they’ll add irresistible crunch and flavor.

Step 6: Top and Broil

Shower the assembled casserole with grated Gruyere cheese, making sure every nook and cranny gets a melty layer. Slide it under the broiler for just a few minutes—stay close!—until the cheese is gloriously golden and bubbling. Nothing beats that scent wafting from your oven.

Step 7: Garnish and Serve

Out of the oven, the Butternut Squash Casserole gets its crowning touch: your fried (or fresh) sage leaves. Scatter them on top and watch as everyone gathers around for a taste of fall perfection.

How to Serve Butternut Squash Casserole

Garnishes

A sprinkle of fried sage leaves is my secret for transforming Butternut Squash Casserole into a real showstopper. They’re crisp, fragrant, and add a pop of elegance with almost no effort. If you don’t feel like frying, fresh sage leaves plucked right before serving give a fresh, herbal accent. You might also dust the top with a little more black pepper or even some toasted nuts like pecans or walnuts for a special touch.

Side Dishes

Butternut Squash Casserole has enough personality to be the star of the meal, but it’s also incredibly versatile. It plays beautifully with a simple green salad tossed in lemony vinaigrette, a loaf of crusty bread to scoop up every delicious bit, or classic roasted chicken or turkey for holiday meals. For a vegetarian feast, pair it with garlicky sautéed greens or wild rice pilaf.

Creative Ways to Present

For a holiday table, try baking your Butternut Squash Casserole in individual ramekins for personalized servings that look fancy but are easy to manage. You can also spoon the mixture into mini pumpkins or squash shells for an unforgettable presentation. And if you’re bringing this dish to a potluck, a cast-iron skillet brings rustic charm and keeps everything warm and cozy.

Make Ahead and Storage

Storing Leftovers

If you have any Butternut Squash Casserole left (which is a big if!), let it cool to room temperature before transferring to an airtight container. It will keep nicely in the refrigerator for up to four days, and the flavors develop even more with time.

Freezing

To freeze, let the casserole cool completely and wrap it well in both plastic wrap and foil or store in a freezer-safe container. Mark it with the date and freeze for up to two months. When you’re ready for another taste of fall, thaw overnight in the fridge.

Reheating

To bring your Butternut Squash Casserole back to bubbling perfection, preheat your oven to 350°F, cover the casserole with foil to keep it moist, and heat for about 20–25 minutes, or until warmed through. Remove the foil for the last few minutes if you want to refresh that golden crust. You can also zap individual portions in the microwave for a speedy comfort food fix.

FAQs

Can I make Butternut Squash Casserole vegetarian?

Absolutely! Just leave out the sausage, or substitute with your favorite plant-based sausage or a cup of sautéed mushrooms. The casserole will still offer loads of depth and flavor thanks to the roasted veggies, sage, and Gruyere.

What’s the best way to peel and cube butternut squash?

Use a sturdy vegetable peeler to remove the thick skin, then cut the squash in half lengthwise, scoop out the seeds, and cut each half into manageable slices and cubes. Sharp knives and a stable cutting board make this job much safer and easier!

Can I use a different type of apple?

While Honeycrisp apples add a lovely tart-sweet bite, you can substitute with Gala, Fuji, or Braeburn—just choose apples that hold their shape when cooked, so they pair well with the tender squash.

How can I make the casserole ahead for a holiday?

Assemble the casserole without broiling the cheese, cover and refrigerate it for up to a day. When ready to serve, let it come to room temperature, then top with cheese and broil as directed. This makes entertaining a breeze!

What’s the best way to reheat leftovers?

Warm individual servings in the microwave or reheat the whole casserole in a 350°F oven, covered in foil, until heated through. If you like your cheese crust extra golden, remove the foil for the last few minutes.

Final Thoughts

There’s something undeniably comforting about gathering around a bubbling Butternut Squash Casserole, watching cheese melt and flavors mingle into pure autumn goodness. Whether you serve it at a festive family dinner or as a weekday treat, this dish is destined to draw rave reviews. Give it a try—you might just discover your new signature casserole!