This post may contain affiliate links. See my disclosure policy.
This easy Sweet Potato Casserole with Marshmallows is the very best Thanksgiving side dish. Creamy mashed sweet potatoes are baked with brown sugar, butter, and warm cinnamon, then finished with a crunchy pecan topping and a layer of gooey mini marshmallows. Best part? You can prepare the whole thing in advance, for an easy make-ahead holiday side dish.
Want more Thanksgiving recipes? Try my easy Thanksgiving Turkey Recipe, Slow Cooker Green Bean Casserole, and our savory old-fashioned Thanksgiving Dressing.
The Best Sweet Potato Casserole with Marshmallows
Let’s be honest – the Thanksgiving turkey is great, but everyone knows it’s the sides that make Thanksgiving dinner worth a second (and third) helping. This sweet potato casserole with gooey marshmallow and crunchy pecan topping is one of my favorites, and one that I make every year. It’s like having dessert for dinner and it’s the perfect balance to more savory sides like fresh green bean casserole, stuffing, and mashed potatoes with homemade gravy.
Plus, it’s make-ahead friendly and incredibly versatile. You can easily adjust the sweetness and richness to your taste – use less sugar and butter for a lighter version, or skip the marshmallows and go all-in on the pecan topping.
Table of Contents
Ingredients Needed
Here’s everything you’ll need to make this easy sweet potato casserole with marshmallows:
For the Sweet Potato Filling
- Sweet potatoes: Use bright orange sweet potatoes (often labeled as “yams” in U.S. grocery stores) for the best flavor and texture.
- Unsalted butter: Adds richness and helps create a smooth, creamy filling.
- Brown sugar: Sweetens the potatoes and deepens the flavor with subtle molasses notes.
- Milk: A little milk lightens the texture and makes the filling silky.
- Eggs: Bind the filling and give it structure while keeping it fluffy.
- Vanilla extract: Adds warmth and enhances the sweetness.
- Ground cinnamon: Brings cozy fall flavor to the casserole.
For the Topping
- Brown sugar: Sweet and caramel-like, it forms the base of the topping.
- All-purpose flour: Helps create that crumbly texture in the pecan topping.
- Chopped pecans: Add crunch and a nutty contrast to the creamy filling.
- Butter: Melts into the topping for a rich, buttery crumble.
- Mini marshmallows: The classic finishing touch – gooey, golden, and irresistible.
How to Make Sweet Potato Casserole with Marshmallows
This delicious sweet potato casserole is easy to make with just a handful of simple and affordable pantry ingredients. Here’s how I make it every time.
Cook the Sweet Potatoes
Start by cooking the sweet potatoes until soft and tender. You can use one of three easy methods:
- Boil: Peel and cube the sweet potatoes, then simmer in a large pot of water until fork-tender (about 15-20 minutes). Drain well.
- Instant Pot: Pressure cook peeled, cubed sweet potatoes for about 8 10 minutes, then quick release and drain. For more information, check out my recipe for Instant Pot Mashed Sweet Potatoes or this Instant Pot Sweet Potatoes recipe for whole sweet potatoes.
- Bake: For deeper flavor, try my Baked Sweet Potatoes method. Pierce whole sweet potatoes with a fork and bake at 400°F for 45-50 minutes, or until soft. Allow them to cool slightly, then peel and mash.
Once cooked, transfer the sweet potatoes to a large mixing bowl and mash until silky-smooth.
Prepare the Filling and Pecan Topping
Combine the melted butter, brown sugar, milk, eggs, vanilla extract, cinnamon, and salt in a mixing bowl. Add the mixture to the cooked and mashed sweet potatoes. Stir until everything is well combined and creamy.
In a separate bowl, combine the toasted pecans, all-purpose flour, brown sugar, melted butter, and a pinch of salt.
Assemble the Casserole
Spread the sweet potato mixture evenly into a greased 9×13-inch baking dish. Sprinkle half of the prepared pecan topping over the top of your sweet potatoes followed by approximately 2 cups of mini marshmallows (more or less to taste), and finally, the last of the pecan topping.
Bake
Bake the casserole at 375°F for 25-30 minutes, or until the marshmallows are puffed and golden brown and the filling is hot and bubbling around the edges.
Variations
Looking to put your own spin on this sweet potato casserole recipe? Try one of these fun and delicious twists to make it your own:
- Gluten-Free Option: Use a gluten-free all-purpose flour blend in the topping and check that your marshmallows are certified gluten-free.
- Nut-Free Version: Skip the pecans or replace them with extra marshmallows or a simple brown sugar streusel for a nut-free twist.
- Naturally Sweetened: Swap some or all of the brown sugar for pure maple syrup for a lighter, more natural sweetness and a hint of rich maple flavor.
- Bourbon Sweet Potato Casserole: Add 1-2 tablespoons of bourbon to the mashed sweet potato filling before baking. The subtle caramel and vanilla notes pair beautifully with the cinnamon and brown sugar.
- Streusel Topping: Replace the traditional pecan topping with a buttery streusel made from flour, brown sugar, oats, and melted butter. Bake until golden for a crisp, crumble-like finish.
Easy to Make-Ahead
This sweet potato casserole recipe is perfect for busy holidays because it can be made entirely or partially in advance. To make it ahead:
- Prepare and mash the sweet potatoes, then mix in the butter, sugar, milk, eggs, and spices as directed.
- Spread the mixture into your baking dish, cover tightly with plastic wrap or foil, and refrigerate for up to 2 days.
- When you’re ready to bake, let it sit at room temperature for about 30 minutes.
- Add the pecan topping and marshmallows, then bake until hot and golden.
If the mixture feels a little thick after chilling, stir in a splash of milk to loosen it before baking.
Tip: You can also make just the mashed sweet potato base up to two days ahead and store it separately from the topping. This makes assembly quick and effortless on Thanksgiving morning.
Easy Sweet Potato Casserole FAQ
Yes. Drain canned sweet potatoes very well and pat them dry, then mash and proceed with the recipe. Since canned sweet potatoes are usually packed in syrup, start with less added sugar and adjust to taste.
You can leave the marshmallows off completely and use only the pecan crumble topping, or replace them with a simple brown sugar and oat streusel. The casserole will still be sweet, rich, and delicious.
Leftover sweet potato casserole will keep in an airtight container in the refrigerator for 4 to 5 days. Reheat individual portions in the microwave or bake larger portions in a 350 degree F oven until hot and the topping has crisped back up.
Yes. Assemble as directed but wait to add the marshmallows. Cover tightly with plastic wrap and a layer of foil or an airtight lid. Freeze for up to 1 month. When ready to bake, thaw overnight in the refrigerator. Remove the wrapping, let it sit at room temperature for 20 to 30 minutes, top with marshmallows and the remaining pecans, then bake at 375 degrees F until hot and bubbly.
Yes. Prepare the recipe as written but cut all of the ingredients in half and bake it in a smaller baking dish, such as an 8 by 8-inch pan. Start checking for doneness about 5 to 10 minutes earlier.
More Sweet Potato Recipes
Hosting Thanksgiving this year? Make it easier and even more delicious with my collection of the Best Thanksgiving Side Dishes and Make-Ahead Thanksgiving Recipes. They’re packed with family favorites you can prep in advance, so you can actually enjoy the big day.
And if you make this recipe, please tell me about it in the comments below. I’d love to hear what you think. Thank you so much! 💛
Sweet Potato Casserole with Marshmallows
Ingredients
- 3 pounds sweet potatoes, peeled and cut into 1-inch cubes
- ⅓ cup brown sugar
- 2 large eggs, beaten
- ½ cup milk
- 6 tablespoon unsalted butter, melted
- 1 teaspoon vanilla extract
- ½ teaspoon ground cinnamon
- 1 teaspoon salt
For the Pecan and Marshmallow Topping
- 1 cup toasted pecans, roughly chopped
- 2 tablespoon all-purpose flour
- 3 tablespoon brown sugar
- 4 tablespoon butter, melted
- 2 cups mini marshmallows
Instructions
- Preheat the oven to 350 degrees F and arrange the oven rack in the center position.
- Grease a large 9×13-inch casserole dish or baking dish. Set aside.
- Thoroughly wash, peel, and chop the sweet potatoes into 1-inch cubes. Transfer to a large pot or Dutch oven and cover with cold water. Bring to a boil, cover, and reduce heat to a simmer. Allow potatoes to cook for approximately 15 minutes, or until tender when pierced with a fork.
- As the potatoes cook, mix together the brown sugar, eggs, milk, butter, vanilla extract, ground cinnamon, and salt. Set aside.
- Drain the cooked sweet potatoes in a large colander and transfer to a large bowl. Use a potato masher to mash the sweet potatoes until smooth.
- Add the brown sugar and egg mixture to the mashed sweet potatoes. Mix thoroughly to combine.
- Transfer the mashed sweet potato mixture to your prepared casserole dish, using a rubber spatula to spread it into an even layer.
- In a separate bowl, combine the toasted pecans, all-purpose flour, brown sugar, melted butter, and a pinch of salt.
- Sprinkle half of the prepared pecan topping over the top of your sweet potatoes followed by approximately 2 cups marshmallows, and finally, the last of the pecan topping.
- Transfer to the oven and bake for 25-35 minutes, or until the tops of your marshmallows are golden brown and the potatoes are heated through.
Notes
- Adjust sweetness: Add more or less brown sugar to taste, depending on how sweet you like your casserole.
- Sweet potato prep: You can make this recipe using mashed baked sweet potatoes or Instant Pot mashed sweet potatoes. Both work perfectly for this sweet potato casserole with marshmallows.
- Make Ahead: You can assemble this sweet potato casserole with marshmallows up to 2 days in advance. Refrigerate covered; then bring to room temp, add the topping, and bake.
- Storage: Store leftovers in an airtight container in the fridge for up to 5 days. Reheat in the oven or microwave until hot.
- Freezer Tip: Freeze without the marshmallows for up to 1 month. Thaw overnight, add the topping, and bake until warm and bubbly.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
I make this every year and the whole dish gets eaten! Thank you for the perfect recipe.
Thanks for the perfect feedback and rating, Cassie 🙂