Butternut Squash Gratin with Leeks, Sage, and Walnuts Recipe

If you’re on the hunt for a cozy, comforting side dish that’s packed full of flavor and texture, you’re going to adore this Butternut Squash Gratin with Leeks, Sage, and Walnuts Recipe. It’s one of those recipes that I turn to when I want something both elegant and incredibly homey — perfect for a holiday feast or a quiet fall evening. Imagine tender slices of butternut squash layered with savory leeks, fragrant sage, creamy sauce, and a delightful crunch of walnuts baked to golden perfection. Trust me, once you try this, it’ll quickly become a staple in your recipe rotation, just like it did in mine!

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Ingredients You’ll Need

The magic of this Butternut Squash Gratin with Leeks, Sage, and Walnuts Recipe comes from simple, fresh ingredients that complement each other beautifully. When shopping, aim for a firm butternut squash without soft spots, fresh leeks (the white and light green parts), and good-quality walnuts. Using real sage leaves really brings the dish to life, but don’t worry if you’re short—dried works in a pinch.

• Butternut squash: Choose one that’s heavy for its size and smooth-skinned for easier peeling and slicing.
• Olive oil or butter: I love butter for that rich flavor, but olive oil keeps it light and vegan-friendly.
• Leeks: Make sure to wash them well—leeks can be sandy inside!
• Garlic: Adds a subtle punch without overpowering.
• Sage leaves: Fresh sage provides the earthy herbal note that defines this gratin.
• Heavy cream or coconut milk: Use heavy cream for richness or coconut milk to keep it vegan without sacrificing creaminess.
• Salt, pepper, nutmeg, and onion powder: These seasonings layer depth and warmth.
• Water: Keeps the squash tender while baking.
• Gruyere cheese (or parmesan/vegan parmesan): Melts into a bubbly, golden topping that’s irresistible.
• Walnuts: Toasted and chopped for that crunchy finish.

Variations

One of the things I enjoy most about this Butternut Squash Gratin with Leeks, Sage, and Walnuts Recipe is how easy it is to adapt. Everyone’s palate is a little different, so feel free to play around with the components to suit your taste or dietary needs. I’ve tried a few tweaks and I encourage you to do the same.

• Vegan version: Swap heavy cream with coconut milk and use vegan parmesan or nutritional yeast for a cheesy flavor—my husband actually prefers this way!
• Nut-free alternative: Replace walnuts with toasted pumpkin seeds for texture and crunch without the risk of nuts.
• Add a spicy kick: Sprinkle a pinch of cayenne pepper or chili flakes in the cream mixture to warm things up.
• Swap the cheese: Parmesan is fantastic, but I also love how aged cheddar adds a sharp, tangy note.
• Make it heartier: Stir in cooked quinoa or wild rice to the layers if you want a more filling side or even a light main dish.

How to Make Butternut Squash Gratin with Leeks, Sage, and Walnuts Recipe

Step 1: Prep Your Veggies with Care

Start by peeling your butternut squash and slicing it into thin 1/8 inch disks—this ensures they cook evenly and layer up beautifully. Trust me, this can be a bit tedious the first time, but the thin slices help create that melt-in-your-mouth texture. Next, clean the leeks thoroughly by slicing and rinsing until all sand is gone. Roughly chop your garlic and finely chop those lovely fresh sage leaves.

Step 2: Sauté Leeks, Garlic, and Sage

Heat your olive oil or butter in a skillet over medium heat, then toss in the leeks and garlic. Cook until the leeks soften but don’t brown—this usually takes about 5-7 minutes. Stir in the chopped sage at the end to release that fragrant aroma right away. This layer adds so much flavor, and it’s worth taking your time here.

Step 3: Create the Creamy Sauce and Season

Mix the heavy cream (or coconut milk) with salt, pepper, nutmeg, and onion powder if you’re using it. This seasoning combo warms the dish and balances the sweetness of the squash. The sauce will envelop each slice, making this gratin rich but not overwhelming.

Step 4: Layer and Bake

In a baking dish, start layering your butternut squash slices, topping each layer with some of the sautéed leeks and sage mixture. Pour a little bit of that cream sauce between layers to keep things moist. Finish off with a sprinkling of grated gruyere cheese and chopped walnuts on top. Add about 1/4 cup water to the dish to help your squash steam gently while baking.

Bake in a preheated oven at 350°F (175°C) for about an hour, or until the squash is tender and the top is golden brown with bubbling cheese. Pro tip: if you like crispy sage leaves, add a few more fresh sage leaves on top halfway through baking to crisp up—they make a stunning garnish!

How to Serve Butternut Squash Gratin with Leeks, Sage, and Walnuts Recipe

Garnishes

I love garnishing this gratin with those crispy sage leaves right from the oven—they add a pop of color and a fragrant crunch. Another favorite is a light drizzle of good-quality olive oil or a sprinkle of freshly grated parmesan just before serving to bring it all together.

Side Dishes

This gratin pairs wonderfully with roasted chicken, pork tenderloin, or even a slice of well-seasoned grilled salmon. For a vegetarian meal, try it alongside a crisp green salad or a hearty lentil stew to round out the plate.

Creative Ways to Present

For special occasions, I’ve served the gratin in individual ramekins—turning out perfectly stacked layers every time, which always impresses guests. Another fun idea is to prepare it the night before, then bake it fresh just before guests arrive so it’s warm and bubbly.

Make Ahead and Storage

Storing Leftovers

I cool any leftover gratin to room temperature before transferring it to an airtight container. It keeps well in the fridge for about 3-4 days. When I’m reheating, a quick zap in the microwave is fine, but I prefer to reheat it in the oven to keep the top nice and crispy.

Freezing

This gratin freezes surprisingly well. I usually flash freeze individual portions on a baking sheet, then move them to a freezer bag. When ready to eat, thaw overnight in the fridge and reheat gently in the oven. Just be mindful that the texture might change slightly—still delicious, but a bit less crisp.

Reheating

For the best texture, I reheat leftovers in a 350°F oven for about 15-20 minutes, covered with foil to avoid drying out, and then remove the foil during the last 5 minutes to crisp up the top. If you’re short on time, microwave it covered, but finish off under the broiler for a minute or two if possible.

FAQs

Final Thoughts

This Butternut Squash Gratin with Leeks, Sage, and Walnuts Recipe holds a special place in my heart because it’s that rare perfect side dish that feels indulgent but isn’t complicated. Whether you’re cooking for a big holiday spread or just want to treat yourself on a chilly night, it’s such a cozy, satisfying dish full of warm, savory notes and delightful textures. I genuinely hope you enjoy making it as much as I enjoy sharing it with you—don’t be surprised if your family asks for seconds (and thirds!). Happy cooking!

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