If you’re looking for a comforting, cozy dish that screams fall vibes but works year-round, then you’re going to adore this Butternut Squash Sage Gratin Recipe. It’s creamy, cheesy, and has that fragrant touch of fresh sage that just makes everything pop. Trust me, when I first tried this, I was hooked instantly—and once you see how simple it is, you’ll be making it on repeat too!

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Why You’ll Love This Recipe

Bursting with Flavor: The creamy fontina and sharp parmesan mix perfectly with earthy sage and sweet butternut squash.
Easy to Make: You’ll be surprised at how simple the steps are, especially making a velvety cheese sauce from scratch.
Perfect for Cozy Meals: This gratin warms the soul and pairs beautifully with a handful of dinner plans, from casual weeknights to special gatherings.
Crowd-Pleaser: My family goes crazy for this dish every time—and I bet yours will too!

The dish is in a dark skillet, showing three main layers. The bottom layer is creamy and white with a thick sauce texture, visible around the edge where some is scooped out. The middle layer is bright orange, soft and smooth, likely mashed vegetables. The top layer is a crumbly golden-brown crust with small green herb bits spread thin and evenly across the surface. The skillet rests on a white marbled texture surface. photo taken with an iphone --ar 4:5 --v 7

Ingredients You’ll Need

Every ingredient in this Butternut Squash Sage Gratin Recipe plays an important role, from buttery layers to the fresh herbal notes. When you shop, pick a firm butternut squash without any soft spots, and grab the freshest sage you can find—fresh herbs make a world of difference here.

Butternut squash: Choose one that’s firm and heavy for its size for the creamiest texture.
Unsalted butter: This helps you control the saltiness of your dish perfectly.
All-purpose flour: Vital for thickening the cheese sauce into that luscious gratin consistency.
Milk: Whole milk works best for that rich, creamy sauce.
Fontina cheese: Melts beautifully and adds a mild, nutty flavor.
Parmesan cheese: Freshly grated, for that sharp, salty kick.
Fresh sage: Chopped finely for aromatic depth—you’ll smell it before you even taste it!
Nutmeg: Just a pinch to enhance earthiness without overpowering.
Ground black pepper: Freshly ground if possible, to brighten the flavors.
Salt: To taste, but remember cheeses add saltiness too.
Panko breadcrumbs: For a crisp, golden topping that contrasts with the creamy layers.

Note: You’ll find the complete list of ingredients, along with their exact measurements, in the printable recipe card at the bottom of this post.

Variations

I love making this Butternut Squash Sage Gratin Recipe custom to whatever mood I’m in or the season. Don’t hesitate to tweak the cheese mix or swap in other herbs to keep it interesting—you might discover your own favorite twist!

Go dairy-free: Replace the butter with olive oil and use a plant-based milk and vegan cheese. It won’t be quite the same, but still delicious.
Herb swap: I sometimes add thyme or rosemary instead of sage for a sharper herbal note that pairs especially well with fall dinners.
Spice it up: Adding a pinch of cayenne pepper or smoked paprika gives a subtle warmth if you enjoy a little kick.
Veggie mix-in: Sometimes, I toss thin slices of sweet potato or parsnip in with the squash for more texture and variety.

How to Make Butternut Squash Sage Gratin Recipe

Step 1: Prep Your Squash and Oven

Start by peeling and slicing your butternut squash into even, thin slices—around 1/8 inch thick works great. Consistency is key here for even cooking! Then, preheat your oven to 375°F (190°C) and butter your baking dish or cast iron skillets so nothing sticks and the edges turn delightfully crisp.

Step 2: Whip Up the Creamy Cheese Sauce

Melt your butter over medium heat, then whisk in the flour until it’s fully absorbed and starts turning a light golden—this usually takes about 2 minutes. This step cooks out the raw flour taste, which is a little trick I learned early on and definitely makes a smoother sauce. Slowly pour in the milk while whisking constantly to avoid lumps, then let it thicken gently. Once thick, stir in the fontina and half the parmesan until silky and completely melted. Add the chopped fresh sage, nutmeg, and black pepper, then taste for salt—you’ll find it varies depending on your cheese’s saltiness.

Step 3: Layer Everything Up

Arrange a layer of butternut squash slices at the bottom of your prepared dish, overlapping slightly like shingles on a roof. Pour about a third of your cheese sauce evenly over the squash, then repeat layering squash and sauce two more times—this layering technique ensures each forkful is perfectly creamy and tender.

Step 4: Add the Crunchy Topping and Bake

Mix the remaining parmesan with your panko breadcrumbs, and sprinkle this evenly over the gratin. Adding a little extra chopped sage on top is a lovely finish if you’re feeling fancy. Cover the dish with foil, place on a baking sheet to catch any drips, and bake for about 30 minutes. Then remove the foil and bake a little longer until the top is gloriously golden and crunchy and the squash is fork-tender. I always let the gratin rest for 5 minutes out of the oven—this helps everything set so it slices beautifully.

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Pro Tips for Making Butternut Squash Sage Gratin Recipe

Thin, Even Slices: I learned that slicing the butternut squash uniformly helps it cook at the same rate and makes layering easier.
Cook Out the Flour: Letting the flour and butter cook for a couple minutes before adding milk avoids that pasty taste in your sauce.
Taste and Adjust: Since cheeses vary in saltiness, tasting the sauce before layering saves you from a too-salty disaster.
Rest Before Serving: Allow the gratin to sit 5 minutes after baking—it settles the sauce and makes serving neat slices so much easier.

How to Serve Butternut Squash Sage Gratin Recipe

Two cast iron skillets sit on a dark wooden surface, each filled with a baked dish that has a creamy, melted cheese base topped with a golden-brown breadcrumb crust speckled with small bits of green herbs. The cheese base is bubbling slightly at the edges, showing a smooth and rich texture beneath the crunchy top layer. Next to the skillets is a yellow cloth with a shiny spoon and fork resting on it, and a few green herb leaves nearby. The scene is cozy and rustic with warm tones and natural lighting. photo taken with an iphone --ar 4:5 --v 7

Garnishes

I usually sprinkle a bit of fresh sage leaves or finely chopped parsley right on top for that pop of color and fresh herbal zing. Sometimes a light drizzle of good-quality olive oil enhances the flavors beautifully as well.

Side Dishes

This gratin pairs nicely with roasted chicken or pork, and a crisp green salad balances the richness perfectly. On chilly evenings, I like serving it alongside a hearty lentil stew for a filling vegetarian combo.

Creative Ways to Present

For special occasions, I’ve baked individual portions in mini cast iron skillets or ramekins. It makes the table look extra cozy and everyone appreciates a personal-sized gratin—plus, it reheats like a charm!

Make Ahead and Storage

Storing Leftovers

Once cooled, I cover leftovers tightly with foil or plastic wrap and keep them in the fridge for up to 3 days. Reheating is a breeze if you follow my method below.

Freezing

I’ve frozen this gratin a few times by wrapping it well and placing in airtight containers. When defrosted, it sometimes loses a little crispness on top but the creamy layers stay delicious.

Reheating

To reheat, I cover the gratin with foil and warm it in a 350°F (175°C) oven for about 20 minutes, then uncover for the last 5 to crisp the topping again. Microwaving is faster but the breadcrumb topping won’t stay as crunchy.

FAQs

Can I use butternut squash puree instead of slices?

Great question! While you could theoretically use puree, this gratin really shines with slices because they hold their shape and create layers that contrast with the creamy sauce. Using puree would give more of a casserole feel, so I recommend sticking with slices if you want the traditional texture.
What can I substitute if I don’t have fontina cheese?

If fontina isn’t handy, mozzarella or gruyère are good stand-ins that melt nicely and have mild, complementary flavors. Just avoid anything too sharp or crumbly so your sauce stays smooth and creamy.
Is it okay to use dried sage instead of fresh?

Fresh sage really elevates the dish with its aroma and vibrant flavor, but if you only have dried, use about a third of the amount. Add it during the sauce step so the flavors have time to infuse.
How do I know when the gratin is fully cooked?

The trick is to check if the butternut squash slices are fork-tender—just slide a fork through a few layers. Also, the top should be golden brown and crunchy. If it’s too pale, give it a few more minutes uncovered in the oven.

Final Thoughts

This Butternut Squash Sage Gratin Recipe is one of those dishes that feels like a warm hug in food form. It’s rich enough to impress but simple enough to make during a busy week, which is why it’s become a staple in my kitchen. I can’t wait for you to try it—you’ll love how the sweet squash and cheesy sauce come together with that hint of sage. Once you get this one right, it might just become your go-to comfort food too. Happy cooking, friend!