Butternut Squash and Sage Gratin

This Butternut Squash and Sage Gratin is a delicious, cheesy side dish similar to scalloped potatoes. Sweet, thinly sliced butternut squash bakes in a creamy Fontina and Parmesan sauce, then gets topped with crunchy panko breadcrumbs and baked until golden. It’s an ideal addition to your Christmas or Thanksgiving dinner table.

Ingredients

• Butternut squash
• Butter
• Flour
• Milk
• Fontina cheese
• Parmesan cheese
• Fresh sage leaves
• Nutmeg
• Salt
• Black pepper
• Panko breadcrumbs

What is gratin?

Any dish prepared the French way, au gratin, means you bake it in cream or milk with cheese. This recipe adds a little twist with panko breadcrumbs for a lovely, crunchy topping.

Gratin serving dish

I recently purchased some small cast iron skillets because they’re just so cute. You can cook in them and serve the food right in the pan. I had a couple of leftover butternut squash from making Thai Butternut Squash Soup, so I came up with this gratin.

If you don’t have cast iron skillets, you can also make the recipe in an 8 x 8-inch (23 x 23 cm) square or oval baking dish.

Tried and true gratin recipe

If you’ve ever made a gratin or scalloped potatoes, you know the milk or cream can curdle and the cheese can separate, creating an oily layer. This is my foolproof recipe that avoids both issues. This gratin recipe has stood the test of time — it’s been a favorite since I first shared it in 2014 and remains just as popular today.

Tips for Making Butternut Squash Gratin

1. Choose the right squash.
Look for a firm butternut squash with a smooth, blemish-free skin. Smaller squash tend to be sweeter and less watery.

2. Slice evenly.
Cut the butternut slices into uniform rounds or cubes so they cook evenly. A sharp knife or mandoline works best.

3. Pre-cook if needed.
If you want to speed up baking, lightly steam or sauté the squash slices before layering—they’ll finish tender in the gratin faster.

4. Preheat oven.
A hot oven ensures the cheese sauce bubbles evenly and the top gets golden and crispy while the squash cooks through

5. Layer thoughtfully.
Start with a layer of butternut squash on the bottom of the pan as a barrier so the sauce doesn’t burn. Alternate squash with cheese sauce in even layers, and don’t overload—too thick a layer may take longer to cook through.

6. Cheese choice matters.
Use a combination of creamy Fontina with Parmesan for richness and a golden crust. A sprinkle of extra Parmesan with the breadcrumbs adds more flavor.

7. Bake uncovered.
This ensures a golden, bubbly top while the interior cooks perfectly. Tent with foil if the top browns too quickly.

8. Let it rest.
Allow the gratin to sit 5–10 minutes after baking; it will firm up slightly and make serving easier.

Instructions for cutting up a whole butternut squash

Slicing butternut squash

When it comes to slicing the butternut squash, I recommend using a mandolin. The thinner the slices, the faster it bakes.

The best butternut squash for gratin

Choose a long-neck butternut squash so you can cut plenty of circles for the gratin. Use a mandolin to get thin, even slices, unless you can slice very thinly with a sharp knife.

Gratin cheese sauce

For the sauce, I took inspiration from the Baked Gnocchi with Sage and Cheese I made last year. The cheese sauce was so good, it had to be repeated.

Best cheeses for gratin

I always recommend using any good melting cheese you enjoy when making a cheese sauce. I can’t always find Fontina at my store, so Gruyère is a delicious alternative. Sharp white cheddar or Havarti also melt beautifully. A reader recently suggested trying a mild Gorgonzola for a unique twist. For the panko topping, Parmesan is the best choice to add a nutty, golden crust.

Panko topping

I choose panko breadcrumbs over regular to add more of a light, crunchy texture on the top of the gratin. To make also use gluten-free breadcrumbs.

The perfect holiday side dish

This creamy Butternut Squash Gratin is the ultimate holiday side dish. Perfect for Thanksgiving, Christmas, or any festive meal, it’s rich, cheesy, and irresistible. Feeding a crowd? Simply double the recipe and bake it in a 9 x 13-inch (23 x 33 cm) dish. It was such a hit at Thanksgiving that it quickly became a Christmas repeat request!

Butternut squash gratin leftovers

Allow the gratin to cool completely before storing. Transfer leftovers to an airtight container in the refrigerator for up to 3–4 days. For longer storage, you can freeze portions in a freezer-safe container for up to 2 months. When ready to eat, reheat in the oven until warmed through to keep the top crispy, or microwave individual servings for a quick meal.

They taste just as delicious when reheated. Warm it in the oven until bubbly, or microwave a single serving for a quick snack. 

Leftovers also make a perfect side for another meal, pairing beautifully with Roast Chicken, Pork, or a vegetarian main.

If you’ve tried my Butternut Squash and Sage Gratin, please leave a star rating in the recipe. You can also leave a comment or ask a question below.

You can also FOLLOW ME on FACEBOOK, TWITTER, INSTAGRAM and PINTEREST to see daily recipe updates.