Butternut Squash Casserole with Apples (Crumble)

Flavor packed butternut squash casserole with caramelized mushrooms, shallots and apples. It's topped with an oat crumble with a little fig jam for a perfect savory and sweet combination! This post was originally published on November 2013 and updated December 2021.

This great butternut squash recipe also shares shortcuts, make ahead tips, ways for roasting butternut squash, and includes an option of 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. And this butternut squash casserole is one of my favorite ways to use it. This article answers the question of how healthy is butternut squash, ways to roast butternut squash and tips for making this casserole.

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How Healthy is Butternut Squash?

It's true that butternut squash is high in carbs, it's also loaded with antioxidants, vitamins (such as Vitamins A and C), and fiber. It's low in calories and has a low glycemic index. This means it's digested more slowly, which keeps blood sugar levels from rising quickly.

I think of butternut squash and sweet potatoes as interchangeable in many recipes. Both are healthy choices, but don't have the same nutrient package. Both pack a nutritional punch, but sweet potatoes are higher in calories and carbs (sugars).

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Roasting Butternut Squash

There are a few ways to approach roasting butternut squash. Deciding which to use largely depends on how you'll use it.

Roasting Butternut Squash Whole

Preheat the oven to 375˚F (190˚C).

Using a sharp chef's knife, slice off the top to remove the stem, and cut the butternut squash in half lengthwise. If the skin is too tough to cut through, place the squash in the microwave for 5 minutes, and try again. The steaming in the microwave should loosen the skin enough to cut through.

Scoop out the seeds and pulp with a spoon. A grapefruit (serrated) spoon works even better, but a regular spoon in your drawer will be fine. Place the squash in a baking dish, cut side up. Brush all surfaces of the squash, except the outer skin with olive oil, and lightly season with salt and pepper.

Roast for 30 - 45 minutes, depending on the size of the squash. If you're in a hurry, you can also add a little water to the baking dish, cover it with plastic, and microwave on high for 10 minutes. Then remove the plastic and slide into the oven to roast for 15 minutes, or until tender.

Roasting Butternut Squash Cubed

Peel the squash using a vegetable peeler. I like the Y-shaped vegetable peelers for this. Then, using a sharp chef's knife, slice off the stem, and cut the squash in half lengthwise.

Scoop out the seeds and pulp with a spoon.

Flip over each butternut squash half, cut sides face down, and slice into ¾" cubes. Place the cubes in a large bowl, drizzle a little olive oil over them and toss with your fingers to completely coat the cubes.

Roasting butternut squash cubes in the oven

Line a baking sheet with parchment paper, and spread the cubes across the sheet, making sure there's space between each cube. Lightly season with salt and pepper. Roast in a 400˚F (204˚C) for 30 - 35 minutes for ¾" cubes. Smaller cubes will roast faster.

Roasting butternut squash cubes in the air fryer

Place the cubes in the air fryer basket and roast in the air fryer at 375˚F (190˚C) for 15 minutes for ¾" cubes.

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Ingredient Notes

Butternut Squash - you only need 4 cups, cubed, so a smaller butternut is perfect. If you have more left over, cut it all into cubes, roast, and save what you don't need for this recipe. Add them to salads, fold into tacos or burritos, or just serve tossed with a little sage as a side.

Or use them, with caramelized shallots or onions to make Butternut Squash Empanadas!

If you prefer, you can use sweet potatoes in place of the butternut, or even cubes of delicata squash (although I haven't tried it).

Mushrooms - you don't need anything fancy here. Button mushrooms work great.

Shallots - if you don't have shallots on hand, use yellow onion instead.

Thyme - feel free to swap this out for other herbs you like with butternut squash and apples.

Balsamic Vinegar - this deepens the umami flavor of this butternut squash casserole, so don't skip this!

Apples - any apple that works great in baking is suggested, except Granny Smith apples. They're too tart for this casserole.

Dried Cherries - you can swap these out for golden raisins, cranberries or dried figs.

Fig Jam - The fig jam adds a wonderful contrasting sweetness with the savory butternut squash - mushroom filling and buttery crumble. Any fig jam will work, since you don't need much of it.

Other Ingredient Ideas

I've made this casserole many times, with numerous variations. Here are some of my favorites.

Stir 1 cup cooked quinoa into the roasted butternut squash to turn it into a main vegetarian / vegan dish. Dot the top with a few little pats of butter. Check this article out for more ideas on increasing the protein content in this butternut squash casserole.

Adding torn shards of kale are another nice addition. Sauté them in the pan with the mushrooms and onion, but only after they've caramelized.

Toss in some cheese before sliding the casserole into the oven. I personally like freshly grated Gruyere.

I've made this with the crumble topping, topped with lattice pie crust, and without any topping at all. We prefer the crumble, followed by no topping at all.

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Technique Notes

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, else they won't caramelize. The pan should be completely dry, and a nice fond developed on the pan when you're done.

It's important to cover the casserole with foil for the first part of the baking process, 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. Much smaller than that, and it's more of a pie crust than a crumble topping.

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Time-Saving Shortcuts

Purchase butternut squash already cubed. Pre-cut squash is typically bigger than ¾", so the roasting and cooking will take a little longer.

It's a personal choice for me to thinly slice the mushrooms and caramelize them. The umami flavor base, for me, elevates the dish. However, you can coarsely the mushrooms instead and just cook until softened with the onion. This takes a fraction of the time - both for prepping and cooking. The tradeoff in the time saved is you lose some of that umami flavor base.

Make the crumble ahead of time, and keep in the refrigerator for up to 1 week.

If making this for a special occasion, make the butternut casserole through the first cooking stage ahead the day before, cool, cover and refrigerate. The following day, bring it to room temperature while you pre-heat the oven, add the crumble, and bake off.

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Equipment

Sharp chef's knife

Vegetable peeler, preferable Y-shaped

8" X 8" baking dish or pie plate

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Want more vegetarian and vegan dish ideas? I can help you. I have three newsletters for different topics: 1) Weekly Recipes, 2) Vegetarian Meal Plans, and 3) Monthly Vegetarian Tips for helping you to move to a more vegetarian diet. Choose which newsletters are most relevant to your lifestyle and you'll also get my 5 SECRETS TO FUSS-FREE VEGETARIAN DINNERS.

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