Impress your guests with a twist on the classic sweet potato casserole. This sweet potato casserole with butternut squash features a silky mash and crumble topping, perfect for any holiday table!

While it might be a bit old fashioned, I still love the idea of a casserole when the temperatures starts to drop. Especially around the holidays when time is short and there are lots of hungry mouths to feed, a warming casserole is always an easy and dependable addition to the table.
This make-ahead sweet potato butternut squash casserole is one of my go-to’s when I’m putting together my holiday menu. Yes it’s technically a sweet potato casserole, but it’s nothing like those sticky sweet marshmallow ones we’ve all come to associate with the holidays.

Sweet Potato Casserole with Butternut Squash
This sweet potato and butternut squash casserole is a savory affair, no sugar or maple syrup or marshmallows in sight. It’s made gratin-style, which is simply the term for topping a dish with bread crumbs and/or cheese (or a mix) and baking until browned and crisp.
And while traditional gratins are typically made with lots of cream, butter, cheese; this one relies on the inherent silkiness of sweet potatoes and butternut squash, along with a dollop of dairy-free yogurt for extra creaminess and a simple almond and nutritional yeast based breadcrumb topping to deliver all the same satisfying richness. Here’s what you’ll need:
Ingredient Notes:
(Here are a few notes about the ingredients you’ll need for this recipe. As always find the full list of ingredients and directions in the recipe card at the bottom of the post.)
- Sweet Potatoes – Look for orange fleshed sweet potato varieties such as Jewel, Beauregard, or Garnet.
- Butternut Squash – You’ll need a small butternut squash halved.
- Olive Oil – For roasting.
- Garlic – For the dish.
- Yogurt – I like to use coconut yogurt but feel free to use your favorite yogurt.
- Topping – You’ll need a combination of almond flour, tapioca, nutritional yeast, olive oil and fresh thyme to create the crumble topping for the casserole.

How to Make a Sweet Potato Casserole with Butternut Squash :
- You’ll start by roasting the sweet potatoes and butternut squash in the oven.
- Next the sweet potatoes and butternut squash are blended together to create a purée.
- Now you’ll mix together the topping by combining the almond flour, tapioca, nutritional yeast, olive oil and thyme until crumbly.
- Pour the puree into a casserole dish, top it with the “breadcrumb” topping and bake until golden and bubbly.
The result is a luxurious silky mash with an irresistibly salty, savory, “cheesy”, crisp crust.
Both the purée and topping can be made the day before and just popped in the oven at the last minute, making it a natural for the holiday table or any harried weeknight meal. It’s s a tasty, savory way to enjoy your sweet potatoes this season.
Variations:
- Use regular yogurt instead of dairy-free for a non-vegan version.
- Omit nutritional yeast if desired and replace with grated cheese for a non-vegan version.
More Holiday Sides:

Sweet Potato Butternut Squash Casserole
With a silky mash and a crumbly topping, this sweet potato and butternut squash casserole is a guaranteed crowd-pleaser!
Ingredients
For the purée:
- 1 Tablespoon/15ml extra virgin olive oil, plus more for the dish
- 1 clove garlic, peeled and cut in half
- 2 small (or 1 large) sweet potatoes, scrubbed and pierced several times with the tines of a fork
- 1 small butternut squash, cut in half, seeds removed
- ½ teaspoon fine sea salt
- ⅛th teaspoon freshly ground black pepper
- ¼ cup/60ml coconut yogurt
For the topping:
- ½ cup/56g almond flour
- 2 Tablespoons/12 g tapioca flour
- 2 Tablespoons/10g nutritional yeast
- 2 Tablespoons/30ml extra virgin olive oil/ ml
- 2 Tablespoons fresh thyme leaves
- ¼ teaspoon fine sea salt
- Pinch of freshly ground black pepper
Instructions
- Heat oven to 400 degrees. Grease a 1 to 1 ½ quart gratin dish with olive oil and rub with cut garlic clove, set aside.
- Place sweet potatoes on a baking sheet and bake for 45 minutes to an hour or until tender when pierced with a knife.
- Rub cut butternut squash with olive oil and sprinkle with salt and pepper. Place butternut squash cut side down on a separate baking sheet. Bake for 45 minutes to an hour or until tender when pierced with a knife.
- Remove sweet potatoes and squash from the oven. Scoop out flesh and place in a food processor or high speed blender along with salt, pepper and yogurt and puree until smooth. You should have about 1lb to 1 ½ of purée. (Purée can be made a day ahead of time.)
- Combine topping ingredients in a bowl, set aside.
- Transfer sweet potato and pumpkin mixture to prepared dish, sprinkle “breadcrumb” topping over gratin.
- Transfer gratin dish to oven, and bake for about 20-25 minutes, or until topping is golden. Remove from oven and serve warm.
Notes
Variations:
Make Ahead:
Mash and crumble topping can be made a day ahead of time and combined prior to baking.
Dietary Info:
Gluten-Free, Grain-Free, Vegetarian, Vegan, Egg-Free, Dairy-Free, Paleo
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Nutrition Information:
Yield:
4Serving Size:
1Amount Per Serving: Calories: 259Total Fat: 16gSaturated Fat: 2gTrans Fat: 0gUnsaturated Fat: 14gCholesterol: 0mgSodium: 279mgCarbohydrates: 25gFiber: 5gSugar: 4gProtein: 6g
Nutritional information for recipes contained on this website, such as calories, fat, carbs, etc. are only estimates and are not guaranteed to be accurate.

Sylvie Shirazi is the recipe developer and food photographer behind Gourmande in the Kitchen. For the last 10 years she's been making eating more healthfully easy and accessible with gluten-free, grain-free, paleo and vegan recipes that are free from processed ingredients.
Charlotte says
Hi!
Just wondering if instead of baking the butternut and the sweet potato I could boil them?
My oven is not working well and the grill is the only option working well, I'm not sure how long it would take if I try baking them!
Thanks!
Charlotte
Sylvie says
Yes you can boil or steam them but the final dish will have less flavor.