Sweet Potato Casserole with Marshmallows and Cinnamon Streusel goes great alongside festive holiday meals or low-key weekday dinners. It’s the ultimate side dish for any meal. Everything except for easy brown sugar streusel can be made ahead.

Sweet potato casserole is a holiday staple, meant to accompany turkey, ham or chicken! Deliciously soft and moist sweet potatoes are simply amazing with brown sugar, vanilla, nutmeg and cinnamon.
Marshmallows and Sweet Potatoes
If you are not a sweet potato person, you will be a fan after tasting them in this sweet potato casserole recipe. And marshmallows are a perfect complement to the sweet potatoes!
That doesn’t come as a surprise at all, since Boston Market restaurant chain uses marshmallows on their signature sweet potato side dish all year long.
How to make Cinnamon Streusel Topping
The combination of melted marshmallows in the topping and the cinnamon streusel is what really makes this dish taste the best.
The streusel is made with flour, brown sugar, cinnamon and nutmeg.
To make Streusel topping, combine 1 cup flour, ¼ teaspoon salt, 1 teaspoon ground cinnamon and 6 tablespoon butter.
Get ready to crumble! Using your fingers rub the butter in the the flour, then add ¼ cups sugar until lumps form. Then stop.
I, on the other hand, really got into it and rubbed the butter into the flour way too effeciently which made it look bread-crumby. Don’t do that unless you like fine crumbs.
You know what else works really well to help make it right? Adding a bit of water will make it more sticky and more clumpy mix that bakes nice and crunchy.
How to make sweet potato casserole
Step 1 is to cook cut up sweet potato pieces until fork tender, about 15 to 20 minutes and then drain them. And then simply add butter, brown sugar, nutmeg and cinnamon.
Mash potatoes with a potato masher (that’s what I used) or blend with an electric mixer, until mostly smooth.
Add heavy cream and combine for another minute until incorporated.
Transfer sweet-potato mixture to a 2-quart baking dish. (To make ahead, refrigerate, up to 1 day.). Top with LOTS of mini marshmallows.
Finally add prepared cinnamon streusel topping.
Bake the sweet potato casserole at 375 F until center is warmed through and marshmallows are lightly browned, 30 minutes.
Health Benefits of Sweet Potato Casserole
Sweet potatoes are some of the healthiest foods you can find on your holiday menu!
Sweet potatoes are an excellent source of vitamin A, which is essential for the immune system and mucus membranes. It also acts as an antioxidant, protecting cells from free radical damage . The potatoes also provide us with vitamin C, manganese, copper, and vitamin B6.
What to serve with the sweet potato casserole
More Holiday recipes
Creamy Bacon Brussels sprouts
Roasted Butternut Squash and Brussels sprouts
Roasted Spatchcock Chicken with Garlic Mustard Crust
Sweet Potato Casserole with Marshmallows and Cinnamon Streusel
Ingredients
Sweet Potatoes
- 5 pounds sweet potatoes, (peeled and cut into 1” pieces)
- 4 tablespoons unsalted butter, (½ stick)
- ½ cup brown sugar
- ½ teaspoon salt
- 1 teaspoon pure vanilla extract
- 1.5 teaspoon ground cinnamon
- ¼ teaspoon ground nutmeg
- ½ cup heavy cream
- 2 cups mini marshmallows
Brown Sugar Streusel Topping
- 1 cup all-purpose flour
- ¼ teaspoon salt
- 1 teaspoon ground cinnamon
- 6 tablespoon unsalted butter, room temperature
- ¼ cup dark brown sugar, (packed)
Instructions
Streusel Topping
- Mix flour, salt, ground cinnamon, butter and dark brown sugar with a fork until a desired crumble texture is achieved. Add more sugar if you want finer crumbs.
Sweet Potatoes
- Bring large pot with water to boil over high heat. Add sweet potato pieces and cook until fork tender, about 15 to 20 minutes.
- Drain potatoes and place them back into pot or large bowl. Mash potatoes with a potato masher or blend with an electric mixer, until mostly smooth.
- Add butter, brown sugar, salt, vanilla extract, nutmeg and cinnamon and using a potato masher, mash until combined.
- Add heavy cream and combine for another minute until well incorporated.
- Transfer sweet-potato mixture to a 2-quart baking dish. Top with 2 cups of mini marshmallows and set aside.
- Preheat oven to 375 F.
Final Assembly
- Top the sweet potato mixture and marshmallows with the prepared crumble topping.
- Bake at 375F until center is warmed through and marshmallows and topping is lightly browned, 30 minutes.
Nutritional information is provided as a courtesy only. This information comes from online calculators. Although whatsinthepan.com attempts to provide accurate nutritional information, these figures are only estimates.
I’m curious as to why the streusel topping can’t be made the night before
Yes, you can and keep in an airtight container in the refrigerator until ready for use.
So excited to try this recipe! Is there a way to substitute the heavy cream?
You can use half and half.
Would there be a way to substitute canned yams for the sweet potatoes? Do you know how much yams you would use? I am cooking everything myself this year, so looking to make it a little easier.
Yes, of course!
Hands down the best sweet potato dish I have ever had. Everyone at my Thanksgiving table agreed—even the people who don’t like sweet potatoes loved this!
So glaaaad it was the best sweet potato dish at your table!!!
Can I make it the day before and just add the toppings the next day and pop in the oven?
Yes, it would be perfectly fine
Can bananas be incorporated in this dish
Yes!
How many people does this serve?
Six large servings.
I thought that sweet potatoes needed more sugar. Other than that, I liked it.
I tried it exactly as the recipe – it reminded me of Boston Market’s sweet potatoes. Very good.
I added pecans into the topping, I chopped them pretty well and really loved it!