This Sweet Potato Casserole With Marshmallows is my favorite version of this classic holiday side dish. It’s filled with warm mashed sweet potatoes, brown sugar, and cinnamon, and topped with ooey-gooey mini marshmallows.
This dish’s recipe twin, Sweet Potato Casserole with pecan crumble topping, is another delicious sweet potato option to add to your Thanksgiving menu if you want to try something a little different.

Sweet Potato Casserole With Marshmallows
What kind of Thanksgiving would it be if there wasn’t a sweet potato casserole on the table? Topping these brown sugar mashed sweet potatoes with gooey marshmallows is my favorite way to prepare this holiday classic. The sweetness of the marshmallow topping mixed with buttery brown sugar and mashed sweet potatoes is a match made in Thanksgiving heaven.
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Another reason to love this side dish is that it’s insanely simple to prep and can even be made a day in advance. Feel free to sprinkle with chopped pecans, if that’s your thing, or leave it as is.
This super traditional Thanksgiving side dish pairs well with other traditional Thanksgiving dishes, such as Grandma’s Stuffing Recipe, Cheesy Potato Casserole, Cranberry Sauce, Make Ahead Mashed Potatoes, and Oven Turkey Breast.

Ingredients You Will Need
- Sweet Potatoes – try and find sweet potatoes that have smooth, copper skin with deep orange flesh. For this recipe, you’ll want to wash and peel before dicing and cooking.
- Butter – we like unsalted butter for this recipe.
- Brown Sugar – we like to use dark brown sugar because of its deep molasses flavor, but you could also use light brown sugar.
- Cinnamon – any kind of ground cinnamon will work.
- Nutmeg – this adds a nice warm flavor.
- Marshmallows – you’ll want to use mini marshmallows for this recipe.
How to Make Sweet Potato Marshmallow Casserole
- Boil the potatoes. Fill a pot with water to cover the diced potatoes and bring to a boil. Continue to boil and cook sweet potatoes for 15-20 minutes, or until they are fork-tender.
- Mash. When the sweet potatoes have finished cooking, strain and put them back into the cooking pot, then use a potato masher to mash the sweet potatoes until they are smooth.
- Make the brown sugar marshmallow topping. In a medium-sized saucepan over medium heat, melt the butter, then add the brown sugar, cinnamon and nutmeg. Bring to boil and boil for 30 seconds, then reduce the heat slightly, add 1 1/2 cups of the marshmallows and continue to cook and stir until the marshmallows are melted.
- Spread over the top. Pour the melted butter and marshmallow mixture into the sweet potatoes and stir until combined. Spread this sweet potato mixture into a 9 x 13″ baking dish and top evenly with the remaining 1 1/2 cups mini marshmallows.
- Bake. Bake in a preheated oven for 15 minutes, or until the tops of the marshmallows are golden brown. Remove from the oven and let cool slightly before serving. Enjoy!

Frequently Asked Questions
Yup! Just spread the sweet potato mixture evenly in your baking dish and let cool completely. Cover with plastic and store in the fridge overnight.
The next day, remove your baking dish from the fridge and preheat the oven to 400 degrees for at least 30 minutes, to give your baking dish time to come to room temperature then finish the recipe as directed.
Both yams and sweet potatoes are root vegetables but are actually not the same thing. Yams come from Africa and Asia and are much more starchy and dry than sweet potatoes. Real yams aren’t often found in grocery stores in the United States, so while your grocery store may label something as a yam, it may not actually be a yam!
Soft Sweet Potatoes: these are the ones with deeper orange flesh inside and often have a copper skin. These are often labeled as “yams” at the grocery store, but they are the ones you will think of when you think of a typical baking sweet potato.
Firm Sweet Potatoes: these have lighter flesh and more of a golden-colored skin.
Long story short – it’s best to just look at how they look and ignore labels! You want to choose the ones that have smooth copper-colored skin with tapered ends.
Peel and cut potatoes into 1-2” pieces. Add potatoes to the pot. Cover with water and boil for 20-30 minutes or until fork tender. Smaller chunks of potatoes will cook quicker and larger chunks will take longer to become fork tender.
Prepared sweet potatoes can last in the fridge for 4-5 days if stored in an airtight plastic container.
Storing and Reheating Instructions
- Make Ahead- Follow the recipe all the way through until just before adding the mini marshmallows on top. Spread the sweet potato mixture evenly in your baking dish and let cool completely. Cover with plastic and store in the fridge overnight.
- Refrigerate- For Leftovers, Cover with an airtight lid or plastic wrap. Leftovers will keep in the fridge for 4-5 days.
- Reheat- Place on a microwave-safe dish and heat for 1-minute increments or until the potatoes are heated throughout.

Sweet Potato Casserole Marshmallow Recipe
Ingredients
- 4 pounds (1,814.37 g) sweet potatoes, peeled and cut into 1" pieces
- 1 cup (227 g) butter
- 1 cup (220 g) dark brown sugar
- 1/2 teaspoon (1/2 teaspoon) ground cinnamon
- 1/8 teaspoon (1/8 teaspoon) nutmeg
- 3 cups (150 g) mini marshmallows, (divided)
Instructions
- Preheat oven to 400 degrees F.
- Wash and peel the sweet potatoes, cut into 1" pieces and add to a large pot. Fill the pot with water to cover the potatoes and bring to a boil. Continue to boil for 15-20 minutes, or until they are fork-tender.
- When the sweet potatoes have finished cooking, put them back into the cooking pot and use a potato masher to mash the sweet potatoes until they are smooth.
- In a medium-sized saucepan over medium heat, melt the butter, then add the brown sugar, cinnamon and nutmeg. Bring to boil and boil for 30 seconds, then reduce the heat slightly, add 1½ cups of the marshmallows and continue to cook and stir until the marshmallows are melted.
- Pour the butter and marshmallow mixture into the sweet potatoes and stir until combined. Spread this sweet potato mixture into a 9 x 13" baking dish and top evenly with the remaining 1½ cups mini marshmallows.
- Bake in a preheated oven for 15 minutes, or until the tops of the marshmallows are golden brown. Remove from the oven and let cool slightly before serving. Enjoy!
Notes
- Storing Leftovers – Cover with an airtight lid or plastic wrap and store in the fridge for 4-5 days.
- Make-Ahead – prepare the recipe without adding the mini marshmallows on top. Cover the baking dish with plastic and store in the fridge overnight, then bake as directed the following day.
- To Reheat- Place on a microwave-safe dish and heat for 1-minute increments or until the potatoes are heated throughout.
Nutrition
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More Sweet Potato Recipes
- Air Fryer Sweet Potatoes
- Best Sweet Potato Fries
- Chili Spiced Sweet Potato Chunks
- Roasted Sweet Potato with Lime and Chipotle
- Sweet Potato Breakfast Casserole
- More Potato Recipes
- More Thanksgiving Recipes
This Sweet Potato Marshmallow Casserole is our favorite version of the holiday classic. The sweetness of the marshmallow topping mixed with buttery brown sugar and mashed sweet potatoes is a match made in Thanksgiving heaven.
Categories:
Christmas, Fall Recipes, Gluten-Free, Holiday Favorites, Nut-Free, Potatoes, Reader Favorites, Sides, Thanksgiving, Winter Recipes,
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