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If you are looking for a vegetable side dish that’s both easy and elevated, look no further than this Butternut Squash Casserole. Layered with pesto and gorgonzola cheese, the flavors come together in an unexpectedly delicious way. This gratin pairs perfectly with a holiday meal or a steak dinner, and it’s naturally gluten free and low carb!

Table of Contents
- Savory Butternut Squash Casserole
- Why You’ll Love this Butternut Squash Gratin
- Butternut Squash Casserole Ingredients and Substitutions
- How to Make Butternut Squash Gratin with Pesto
- Storing and Reheating Leftovers
- Make it a Meal – What to Serve with Butternut Squash Casserole
- Get the Recipe
- More side dish casseroles
Savory Butternut Squash Casserole
This recipe is inspired by Giada DeLaurentiis’ Butternut Squash Gratin with Pesto from her cookbook Giada’s Family Dinners. I’ve made it many times and we always enjoy it. But I wanted to give the casserole a flavor twist by using a homemade sage pesto (though a jar of your usual basil pesto will work beautifully) and some creamy gorgonzola. Giada’s version is amazing, but this one will knock your sock off.
Cuisine Inspiration: Italian-American
Primary Cooking Method: Stove, Oven
Dietary Info: Gluten-free, Low-carb, Egg-free
Skill Level: Easy
Why You’ll Love this Butternut Squash Gratin
My entire family devours this dish – yes, even the kids! Here’s why I think you’ll enjoy it too.
- Easy to prepare. Prep is a breeze – you only need to layer a few ingredients. And while it’s amazing with the homemade sage pesto for a little different flavor profile, you can just use your favorite jar of basil pesto.
- Fresh and wholesome ingredients. Yes, this naturally gluten free and low carb side highlights the flavor of the squash by keeping it simple with just salt and pepper, the pesto, and the cheese. It’s not weighed down with heavy ingredients.
- Prep ahead. Once you’ve assembled the butternut squash casserole, you can keep it in the refrigerator and then bake it when you are ready to serve it. Perfect for the holidays!
Butternut Squash Casserole Ingredients and Substitutions
The ingredient list is short, even if you make the pesto from scratch. Here’s a quick overview of what you’ll need. Scroll down to the recipe card for the full amounts and detailed instructions.
- Butternut squash. It’ll need to be peeled, seeded, and cut into large chunks. You can use a package of pre-cut pieces to make it easier.
- Kosher salt and pepper. To taste.
- Pesto. The ingredients for the sage pest are below. Or use a jar that you pick up at the grocery store.
- Gorgonzola cheese. You can use another type of blue cheese. And if you aren’t a fan of blue cheese, feel free to experiment with goat cheese, parmesan, mozzarella, or whatever you enjoy.
For the sage pesto:
- Fresh sage leaves
- Chopped walnuts. You can substitute pine nuts like in classic pesto.
- Kosher salt and pepper.
- Olive oil.
- Parmesan cheese.
How to Make Butternut Squash Gratin with Pesto
Get ready by preheating the oven to 350°F, and coating an 8-inch baking dish with olive oil or cooking spray. Now let’s get cooking.
- Prepare the pesto. If you are making the sage pesto, combine the sage leaves, walnuts, olive oil, and a pinch of salt and pepper in a blender or food processor. Stir in the cheese and adjust the seasoning.
- Cook the squash. Steam the squash in a steamer basket set in a post with a couple of inches of simmering water until very tender. Transfer it to a blender or food processor and puree until smooth, then season with salt and pepper.
- Layer and bake. Spread half of the squash in the pan, top with half of the pesto and half of the cheese. Repeat the layers. Bake the butternut squash casserole until heated through and browning around the edges.
Storing and Reheating Leftovers
You can cover any leftovers and store it in the refrigerator for two or three days. It can be reheated in the microwave or oven until it is hot and steaming all the way through.
You can even prepare the butternut squash casserole in advance and refrigerate it until you are ready to serve it. If you put it in the oven straight out of the refrigerator, you will likely have top add a few minutes to the cooking time to ensure it gets hot all the way through.
I would not recommend freezing it.
Make it a Meal – What to Serve with Butternut Squash Casserole
This is a celebration-worthy dish, whether you pair it with a holiday prime rib or a date night in. You’ll definitely impress when you add it to any of these menu ideas:
- Holiday Roast. Whether you make a classic Baked Ham or a savory Bottom Round Roast, this side will turn it into a gourmet dinner.
- Steak Dinner. Your meal at home becomes restaurant-worthy when you make Balsamic Marinated Flat Iron Steak or some Grilled New York Strip Steaks.
- Italian Meal. Since this gratin has Italian inspiration, you can pair it with Italian fusion dishes like Balsamic Pot Roast or a savory Braciole.
Butternut Squash Casserole with Pesto and Gorgonzola
Ingredients
For the gratin:
- 3 pounds butternut squash, peeled, seeded, and cut into large chunks
- kosher salt and pepper
- 1/4 cup sage pesto
- 4 ounces crumbled gorgonzola cheese
For the sage pesto (makes about 1/2 cup):
- 1 cup packed fresh sage leaves
- 2 tablespoons chopped walnuts
- 1/4 teaspoon kosher salt
- 1/8 teaspoon pepper
- 1/3 cup extra virgin olive oil
- 1/4 cup parmesan cheese
Instructions
For the gratin:
- Preheat oven to 350°F, and coat an 8-inch baking dish with olive oil or cooking spray.
- In a large pot with a steamer insert, bring a couple of inches of water to a boil, add the squash to the steamer rack, and steam about 20 minutes, until very tender.
- Transfer squash to a blender or food processor and puree until smooth. Season with salt and pepper to taste.
- Spread half of the squash in the prepared dish. Top with half of the pesto, dropped in small dollops then carefully spread over the squash. Sprinkle half of the cheese over the pesto.
- Repeat the layers.
- Bake for about 40 minutes, or until heated through and browning around the edges.
For the sage pesto (makes about 1/2 cup):
- In a blender of food processor, combine all of the ingredients except the cheese and puree until smooth.
- Stir in the cheese, and adjust seasoning with salt and pepper to taste.
Sage pesto, very different, Brianne!
It was so good!!
Ooh I love your sage pesto with the walnuts!!Gorgonzola seems like a great idea for your gratin too.Delicious flavors going on all around!
We enjoyed the sage pesto on pizza too!
Sage and butternut squash were meant to be together. This gratin sounds like such a perfect side dish to add to my menu this year.
I agree, I love squash and sage!
Oh wow… I love the flavors in this! 🙂
Thank you so much for sharing at Marvelous Mondays this week- Pinned!
Thanks Carrie!
what a unique dish – I LOVE the blue cheese
Can you ever go wrong with blue cheese?
So many yummy flavors in this! Thanks for sharing.
Thank you Marjory.
Ok, seriously would have never thought of mixing those flavors but sometimes those are the best combinations. {the ones we never think of that is} Looks delicious! Pining this and totally need to give it a try! Thanks Brianne!
Thanks Krista!