By: Jill Mills Updated: Nov 25, 2025

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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.

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?!

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!

Why You’ll Love This Sweet Potato Casserole Recipe

The Topping – We have always gone back and forth wanting a pecan streusel topping or marshmallows. Combining the two is a perfect solution! If you have family members that do not like one or the other, just do one side marshmallow and the other side pecans.
Sweet and Savory – Some sweet potato casseroles are way too sweet for my liking but this recipe is the perfect balance of sweet and savory. I add small amount of brown sugar and maple syrup to the actual mashed sweet potatoes and then the pecan streusel and marshmallows also sweeten the dish. The crunch of the pecans and the gooey marshmallows is the perfect texture combination too.
Easy to prepare – This recipe comes together quickly and looks very impressive!

Ingredients Needed

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.
Salt and Vanilla Extract
Sugars – light brown sugar and maple syrup.
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.

How To Make Sweet Potato Casserole

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, brown sugar, maple syrup, egg and salt. Mash well.

mashed sweet potato mixture in a baking dish

pecan streusel sprinkled over sweet potatoes in a baking dish

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!

Common Questions

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!

Should I Whip or Mash the Sweet 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!

Make-Ahead Instructions

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.

Variations

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.

Sweet Potato Casserole on a plate with a fork

Serving Suggestions

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.

This also goes well with other holiday sides, like green bean casserole and 30 Minute Dinner Rolls.

Storing, Freezing and Reheating

Storing – 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.
Reheating – 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.
Freezing – 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.

Sweet Potato Casserole with Marshmallows and Pecans