This Sweet Potato Casserole with Marshmallows and Pecans is the best of both worlds. Buttery, cinnamon-spiced sweet potato mash is topped with a sweet pecan streusel and finished with marshmallows toasted to golden brown perfection. Perfect for Christmas and Thanksgiving. Make ahead instructions included!
The Best Sweet Potato Casserole with Marshmallows
This Sweet Potato Casserole with Marshmallows and Pecan Topping has a little bit of something for everyone. Creamy mashed sweet potatoes, crunchy and sweet pecan streusel, and gooey marshmallows. What’s not to love?!
Some sweet potato casseroles are way too sweet for my liking but this recipe is the perfect balance of sweet and savory. I don’t add any sugar to the actual mashed sweet potatoes and instead, let the pecan streusel and marshmallows sweeten the dish. The crunch of the pecans and the gooey marshmallows is the perfect texture combination too.
This casserole makes its way to our dinner table for every holiday, whether it’s Thanksgiving, Christmas, or Easter, and I’ll even admit to making it once or twice throughout the year as well. It’s that good!
Here’s what you’ll need to make the Sweet Potato Casserole with Pecan Streusel and Marshmallows (the exact measurements and full recipe instructions are below in the printable recipe card):
- Sweet potatoes – I recommend fresh, not frozen or canned sweet potatoes for this recipe.
- Butter – Gives the side dish a rich flavor.
- Milk – Milk helps to give a creamy texture to the mashed potatoes.
- Cinnamon – Adds a warm flavor to the side dish, that pairs nicely with the brown sugar and pecan topping.
- Brown sugar – I used light brown sugar, but dark brown sugar works as well.
- All-purpose flour
- Pecans – You can buy the pecans already chopped to save time!
- Mini marshmallows – If all you have is regular-sized marshmallows, cut them into quarters (or smaller) so they toast perfectly.
Are Yams and Sweet Potatoes the Same Thing?
Yes…and no. In the United States, yams and sweet potatoes are used interchangeably, usually describing a potato with red-brown skin and orange flesh. There are also ones that have a lighter yellow skin with orange flesh, which are still the same thing and are called yams or sweet potatoes as well.
“Real” yams have brown or black skin with flesh that’s usually red or purple but you won’t usually find those in the US or Canada.
Can I Use Canned Sweet Potatoes?
Canned sweet potatoes can be used, though note that the texture may be a bit different. I prefer to always use fresh sweet potatoes for the best flavor and texture but in a pinch, the canned version will do fine. Just be sure to double-check the label and grab a can that does not have any sugar added or the dish will end up way too sweet!
There are many different sweet potato casserole recipes out there and several ways to customize this one to meet your desired preferences.
- Switch or omit the nuts. If you prefer walnuts over pecans, use chopped walnuts in the streusel topping. Alternatively, you can omit the nuts completely if desired.
- Make it creamy. You can use heavy cream instead of milk to give the sweet potato casserole a richer, creamier flavor and texture.
- Add more spice. For a variety in flavor, try using pumpkin pie spice instead of cinnamon.
- Skip the marshmallows. Prefer your sweet potato casserole without marshmallows? Just skip them and let the pecan streusel be the focus.
How to Make Sweet Potato Casserole with Marshmallows and Pecans
One of the reasons I volunteer to make sweet potato casserole for every holiday is because it’s such an easy side dish to make. Many of the steps can even be prepared in advance!
- Cook the sweet potatoes. Prepare the sweet potatoes by washing, peeling, and cutting them into 1-inch chunks. Bring to a boil over high heat, then reduce to a simmer until the potatoes are fork-tender.
- Mash the potatoes. Drain the potatoes then return to the pot. Add the butter, milk, cinnamon, and salt. Mash well.
- Add the topping. Spread the mashed potatoes in a baking dish. In a separate bowl, combine the butter, flour, brown sugar, and cinnamon. Stir in the pecans. Sprinkle the topping over the sweet potato mixture.
- Bake. Bake for 10 to 12 minutes. Add the mini marshmallows, then bake for another 5 to 6 minutes, until golden brown. Keep a close eye on them as the marshmallows can burn quickly.
- Enjoy. Let the casserole cool for 5 minutes or so, then serve and enjoy!
Should I Whip or Mash the Potatoes?
If you like your sweet potatoes very smooth and creamy, whip them with an electric mixer instead of mashing them by hand with a potato masher. Mashing by hand usually produces a thicker textured sweet potato mash with some lumps. Make them the way you like!
As I mentioned above, one of the reasons I love this side dish so much is that about 90% of the recipe can be prepared in advance. This is perfect for the holidays, as you can do all of the work the night before, then just pop it in the oven the next day.
To make your sweet potato casserole with marshmallows in advance, follow the directions up until baking. Mash the sweet potatoes, assemble them in the baking dish, and add the pecan streusel. Then cover tightly with foil and place in the fridge overnight.
The next day, just pop the dish in the oven and finish the recipe as directed. Note that you may need to add a few minutes to the original bake time if the dish is cold when you put it in the oven.
This sweet potato casserole is best served soon after baking when the marshmallows are still warm and gooey. It’s the perfect side dish for the holidays, next to a Thanksgiving turkey or Christmas ham, though it would pair well with steak or chicken breast throughout the year.
How to Store & Reheat Leftovers
Leftover sweet potato casserole can be kept in the fridge for up to 5 days. Be sure to cover the baking dish tightly with plastic or transfer the leftovers to an airtight container.
If reheating the entire baking dish, it’s easiest to do so in the oven. Cover and reheat at 350F until heated through.
For individual servings, it’s easiest to just reheat them in the microwave.
Can I Freeze Sweet Potato Casserole?
Yes, sweet potato casserole can be frozen, both before and after baking. To freeze before baking, follow the make ahead instructions mentioned above, wrap the dish tightly in plastic wrap and foil, and freeze for up to 4 months. Add the marshmallows after baking.
To freeze after baking, allow it to cool completely, then wrap tightly in plastic wrap and foil. Freeze for up to 4 months.
In both cases, you can bake directly from frozen. You’ll just need to add extra baking time. To prevent burning, keep the pan covered with foil (but remove the plastic!) while baking.
More Thanksgiving Side Dishes:
- Honey Butter Skillet Corn
- Instant Pot Cranberry Butter
- 30 Minute Dinner Rolls
- Cornbread Dressing
- Crockpot Mashed Potatoes
- Baked Mac and Cheese
Sweet Potato Casserole (Pecan Streusel and Marshmallows)
- Wash, peel, and cut the sweet potatoes into 1-inch chunks. Place the sweet potatoes into a large pot and cover with water. Heat the pot on the stove over high heat until boiling. Reduce the heat to medium-high and simmer until the sweet potatoes are fork-tender.
- Pour the sweet potatoes into a colander to drain off the water, then return the sweet potatoes to the pot. Add the butter, milk/cream, cinnamon, and salt. Mash well with a potato masher or whip with an electric mixer.
- Preheat the oven to 375ºF. Grease a 3-quart baking dish with non-stick cooking spray.
- Spread the mashed sweet potatoes evenly in the prepared baking dish.
- In a medium mixing bowl, combine the butter, flour, brown sugar, and cinnamon with a fork until crumbly. Stir in the chopped pecans.
- Sprinkle the streusel topping over the sweet potatoes.
- Bake the casserole at 375ºF for 10-12 minutes until hot. Top with the mini marshmallows then bake for an additional 5-6 minutes until the marshmallows are toasted golden brown on top. Watch the marshmallows closely while baking; they can burn quickly!
- Remove the casserole from the oven and cool for 5 minutes before serving.