This flavor-packed vegetarian butternut squash casserole includes caramelized mushrooms, shallots, and apples. It's all topped with an oat crumble mixed with a little fig jam for a perfect savory and sweet combination!
This delicious recipe also shares shortcuts, make-ahead tips, and ways to roast butternut squash, and an option for including quinoa for a vegetarian main dish.
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I roast up a lot of butternut squash during the fall and early winter months. It makes an excellent savory soup, turns a side salad into a main vegetarian salad entree, a simple roasted butternut squash and red onions dish into a stunning main with chickpeas, and hasselbacked butternut squash is a beautiful, special dinner.
This vegetarian butternut squash casserole recipe is another of my favorite ways to use roasted butternut all through autumn. It's also an excellent side dish for Thanksgiving.
❤️ Why you'll love this recipe
- Flavorful. This casserole is a balance of savory and sweet, to satisfy everyone at the table.
- Make-ahead. Make it ahead, and rewarm when ready to serve.
- Main or side dish. Add cooked quinoa to the casserole and serve it as a cozy weeknight dinner. Or serve as a side dish for the meat lovers at the table.
- Thanksgiving dinner. This casserole is a great comfort dish for your holiday table.
🧅 Main Ingredients + Notes
The secret to faster and easier meals often lies in the ingredients. For example, store-bought items and ingredients you make ahead and store in the refrigerator (or freezer) can turn a 60-minute recipe into a 30-minute meal or less.
For all of the ingredients, measurements, and directions, go to the Recipe Card at the bottom of this post.
Butternut Squash Casserole
- Butternut squash - since you only need 4 cups, a smaller butternut squash is all you need.
- Cremini mushrooms - other mushrooms work well too, such as white mushrooms or shiitake mushrooms. Feel free to use your favorites.
- Shallots
- Fresh thyme
- Vegetable broth - or Better Than Bouillon - Roasted Vegetable Bouillon Paste.
- Balsamic vinegar - you don't need much, so you don't need one of the expensive ones. I always have fig balsamic vinegar on hand, and is my favorite for this casserole.
- Honeycrisp apples - or other apples suitable for baking, such as Fuji, Pink Lady, or Braeburn apples. Granny Smith apples are too tart for this recipe.
- Dried cranberries - or dried cherries.
Crumble Topping
- All-purpose flour
- Rolled oats - don't use Instant Oats
- Brown sugar - purchase or make your own brown sugar!
- Fig jam - purchase or make your own spiced fig jam.
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🔪 Recommended Equipment
Having the right equipment for recipes makes prepping so much easier. If you want more fuss-free prepping and cooking, check out my updated list of favorite kitchen tools and equipment.
📝 Instructions Overview
Detailed instructions for making this butternut squash dish are in the recipe card below, but here's an overview!
Step 1
Butternut squash. Peel, cube, and air fry the butternut squash. If you don't have an air fryer, roast in a 400˚F oven until tender. The exact amount of time will be dependent on the size of the butternut squash cubes, but a good rule of thumb is 20 - 25 minutes in the oven and around 10 - 12 minutes in the air fryer.
Step 2
Sauté. Prep the mushrooms and shallots, and sauté until lightly caramelized and the pan is dry. Wait until a fond develops on the bottom of the pan, and stir in the broth, balsamic vinegar, and thyme. Be sure to scrape up the fond as you stir everything together, as it's full of savory, umami flavor.
Step 3
Combine. Add the roasted butternut squash, apples, and dried cranberries to the mushrooms and shallots and gently stir together.
Step 4
Bake. Transfer the butternut squash mixture to a casserole dish or deep pie plate. Drizzle additional vegetable broth over the squash, cover, and bake.
Step 5
Crumble. Make the crumble, and spread it over the butternut squash casserole. With the casserole dish still uncovered, bake until the crumble topping turns a golden brown.
👩🍳 How to Prep Butternut Squash
- Slice off the top and bottom of the squash. If the skin is too tough to do this easily, pop it into the microwave oven for a few minutes to soften the skin.
- Stand the squash up on end, and cut it in half lengthwise. Scoop out the seeds and pulp with a spoon.
- Lay the squash down flat, and peel it with a vegetable peeler. I prefer to use the Y-shaped peelers for this.
- With the cut side of the squash facing down on a cutting board, slice it into ¾" cubes.
⏰ Tips to Simplify and Save Time
- Purchase butternut squash already peeled and diced. If they are cut into large cubes, you may need to cut them a little smaller. The ideal size is ¾".
- Coarsely chop pre-sliced mushrooms.
- Make the crumble ahead of time, and keep it in the refrigerator for up to 1 week.
- Bake the casserole until it's time to add the crumble, cool to room temperature, and cover tightly. Refrigerate for up to 2 days. When ready to finish the dish, bring it to room temperature, add the crumble, and finish baking.
👩🍳 Cooking Tips
- Caramelizing the mushrooms and onions together takes a little time, but it's time well spent. This is the umami flavor base for this butternut squash casserole. As they cook, be sure not to move them around much, or they won't caramelize. When you're done, the pan should be completely dry, with a nice fond on the bottom.
- Covering the casserole with foil for the first part of the baking process is important, as this will help keep the casserole moist.
- Combine the crumble ingredients with your fingers or a pastry blender only until the butter pieces are about the size of a pea. When the crumble pieces are smaller, the topping bakes up more like a pie crust than a crumble.
💡Ideas for Possible Variations
- Substitute delicata squash or kabocha squash for the butternut, or use sweet potatoes.
- Golden raisins, dried figs, and dried cherries all are great in this casserole in place of the dried cranberries.
- Tear up dinosaur kale leaves, discarding the central stem, and sauté them in the pan after the mushrooms and shallots caramelize. Or use baby kale.
- Add cheese before sliding the casserole into the oven. Gruyere is a great choice, or if you add black beans to make it a main dish, use Monterey Jack cheese.
- Turn this vegetarian side dish into a main dish by stirring 1 cup of cooked quinoa into the caramelized mushrooms and shallots (shown below). Alternatively, add 1 cup of cooked black beans. Check this article out for more ideas on increasing the protein content in this butternut squash casserole.
- Add pumpkin seeds (pepitas) or roasted pecans for a nutty flavor.
🥬 Make it Vegan
Make this a vegan butternut squash casserole by eliminating the crumble topping.
🤩 Leftovers
Store any leftovers in an airtight container and keep in the refrigerator for up to 2 - 3 days. After that, the crumble topping turns soggy.
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Vegetarian Butternut Squash Casserole with Apples
Equipment
- 8" X 8" Casserole dish 9-inch deep dish pie plate
Ingredients
Butternut Squash-Apple Filling
- 4 cups peeled and diced butternut squash diced into ¾" pieces
- 1 tablespoon avocado oil or other high heat cooking oil
- 2 tablespoons unsalted butter plus more for buttering the pie dish
- 1 cup thinly sliced mushrooms or coarsely chopped
- 1 cup finely chopped shallots 2 - 3 large shallots
- 1 teaspoon kosher salt divided (or ½ teaspoon table salt)
- ½ teaspoon Better Than Bouillon Vegetable Bouillon Paste, divided (or vegetable broth or water)
- 1 teaspoon balsamic vinegar
- 2 teaspoons chopped fresh thyme
- 3 cups thinly sliced apples cored but unpeeled (see Ingredient Notes)
- 3 tablespoons dried cranberries
Crumble Topping
- ⅓ cup all-purpose flour
- ⅓ cup oats
- 1 tablespoon brown sugar
- ½ teaspoon kosher salt or ¼ teaspoon table salt
- 4 tablespoons unsalted butter, room temperature
- 1 tablespoon fig jam or just add another tablespoon brown sugar
Instructions
- Preheat the oven to 375˚F (190˚C) and generously butter a 9" pie plate or an 8" X 8" oven-safe casserole dish.
- Prep the squash. Peel and cube the butternut squash. (See the How to Prep Butternut Squash section in the post if you need tips on the best way to do this.) Place the diced butternut squash in a large mixing bowl and toss with only enough avocado oil to completely coat the squash.
- Cook the butternut squash.Instructions for air frying butternut squash: Preheat the air fryer to 375˚F (190˚C). Arrange the butternut squash in the air fryer basket in an even layer. The more spread out the squash is, the better it will roast. Air fry for 12 minutes or until lightly caramelized, shaking the basket halfway through cooking. Set aside. Instructions for roasting butternut squash in the oven: Preheat the oven to 400˚F. (The oven is already preheating to 375˚F to bake the casserole, so if you roast the squash in the oven, lower it back to 375˚F after the butternut squash roasts.) Line a rimmed baking sheet with parchment paper, and spread the diced butternut squash across it. Roast for 15 - 20 minutes until tender, depending on the size of the diced squash. Set aside.
- Sauté the mushrooms. Melt the butter in a large skillet over medium heat. Add the sliced mushrooms, shallots, and ½ teaspoon kosher salt (¼ teaspoon table salt). Cook until the shallots and mushrooms soften and melt into the butter.Once they reach this stage, continue to cook them, but only move the mushrooms and shallots around the pan every 5 minutes. This allows them to caramelize. A brown fond will develop on the bottom of the pan as it becomes dry.Stir in ¼ cup water and ¼ teaspoon Better Than Bouillon paste or ¼ cup vegetable broth and scrape up the bits of fond from the bottom of the pan. Stir in the balsamic vinegar and fresh thyme.
- Combine. Add the roasted butternut squash to the pan along with the apples and dried cranberries. Toss to mix in the pan so the the caramelized mushrooms coat everything well.
- Bake. Transfer the squash filling into the prepared pie plate or casserole dish, and add the final ¼ teaspoon of Better Than Bouillon paste diluted in ¼ cup water (or ¼ cup vegetable broth). Cover with foil and bake for 10 minutes.
- Crumble.Whisk together the flour, oats, brown sugar, and salt in a small bowl.Slice the butter into thin pieces and add to the mixture. Pinch the butter in the mixture using your fingers or a pastry blender until the crumble is coarse. Some chunks of butter should be the size of peas.Gently stir in the fig jam.
- Finish. Remove the butternut squash casserole from the oven, and uncover it. Scatter the crumble over the top of the casserole and return it to the oven for another 15 minutes, or until the topping is golden brown.Serve warm.
Renee
I think I'd eat half of this before it got to the table too. What a lovely recipe!
The Wimpy Vegetarian
Thanks Renee! I'm making it again this afternoon 🙂
angela@spinachtiger
Butternut squash and apples are simply meant to go together. And, I love the addition of those dried cherries.
The Wimpy Vegetarian
Thanks Angela!!
Jennifer @ Peanut Butter and Peppers
Squash crumble! What a perfect dish!! I love it and I would probably eat the whole thing!!
The Wimpy Vegetarian
Thanks Jennifer! I almost did eat the whole thing. I had to remind myself that my husband would probably want some too... 🙂
Dorothy at Shockingly Delicious
This looks magnificent!
The Wimpy Vegetarian
Thanks Dorothy!!
Susan 30A EATS
Sinfully delicious! what a great fall recipe and perfect for Thanksgiving!
The Wimpy Vegetarian
Thanks so much Susan!!
Heather // girlichef
Oh, I was SO looking forward to seeing this recipe - and it does not disappoint! It's so beautiful, and it's definitely going on my must-try list.
lizthechef
I am all over this one, girlfriend!
Paula @ Vintage Kitchen Notes
I saw a savory squash crumble on La Tartine Gourmande last year and thought it was such a cool idea. Now this one looks sensational Susan! Your pics are always so tempting!
Shannon R
I love the apple! What a great idea. Thanks for the awesome recipe!
Laura Dembowski
The flavors in this sound so good together! Love the fig jam in the crumble along with the time. This would be a magnificent Thanksgiving side dish!
Tara
I was looking forward to see this recipe and man it looks so good!! Perfect side dish for so many meals!!!
Liz
What a gorgeous crumble! I'd be right there with you doing quality control!!!
Choc Chip Uru
Mmm, this looks like a delicious crumble, so warm and sweet 😀
Cheers
CCU
Sarah
Never tried a savoury crumble but it looks delicious
kathia Rodriguez
This could be a new side dish on my holiday table
Kim@Treats & Trinkets
I can't help myself when it comes to making changes to recipes, either. This sounds so good!
Sunithi
look really good Susan! Love the addition of ginger. I may make this one of my thanksgiving sides!
Jane's Adventures in Dinner
This is so brilliant! I've never thought of a savoury crumble before but how clever.
Family Foodie
This crumble looks amazing! I would eat it all by myself. This is perfect for the holidays too!
Shaina
What a beautiful fall-inspired dish!
Soni
Ooh Susan I'm in love with all the things you've put in your crumble!!I would love to try this dish to taste all those lovely flavors with the ginger and thyme.So so good.I would eat a third too 🙂
mjskit
At first I thought this was a sweet crumble, but was thrilled to see that it's a savory one. What a great dish for the holiday table. Very festive but different. Thanks!
Sarah | The Sugar Hit
This looks so gorgeous! Perfect for a non-pie addition to the thanksgiving table!
Katie
This turned out beautifully....and sounds like the perfect dish right around this time of year! Love love love it....
apuginthekitchen
What a beautiful recipe Susan, I just love butternut and apples combined and your crumble is sweet and savory and a delicious combination of textures and flavors. How perfect this will be on the Thanksgiving table.
Brianne @ Cupcakes & Kale Chips
I love the addition of mushrooms to the squash. This looks so good.
Laura
Oh wow a savoury crumble recipe, this sounds fantastic.
Cindys Recipes and Writings
Love the fig in there, Susan!
Cass @foodmyfriend
This looks super comforting. I would eat it on the couch, wrapped up in my yellow throw blanket 🙂
Alaiyo Kiasi-Barnes
I don't think I would have been able to stay away from this pie for long. I would have eaten more than half. Looks delicious!
Nora @ natural noshing
What a fantastic recipe! I had you for the secret recipe club this month, and couldn't have enjoyed this more! Made a few substitutions to make it gluten-free and dairy free, and I'll be making this for years to come! Thanks so much, happy reveal day!! 🙂