This Sweet Potato Casserole with Marshmallows and Pecans has everything my family wants at the Thanksgiving table. The sweet potato filling is buttery and cinnamon-y, then you get that brown sugar pecan layer underneath a whole blanket of toasted marshmallows. Absolutely delicious (almost like dessert, haha)!
It’s also one of those holiday sides that’s nice to get partly out of the way ahead of time. You can prep the sweet potato filling in advance and then simply add the pecan topping and marshmallows right before baking.
And because this version gives you both toppings, you don’t have to choose between crunchy pecans or gooey marshmallows. I always grab the scoop with both, obviously!
Why You’ll Love This Sweet Potato Casserole
- You get both toppings. A buttery brown sugar pecan layer sits under the marshmallows, so you get a little crunch with that soft, gooey topping in every scoop.
- Great for holiday prep. You can make the sweet potato filling ahead of time, then add the pecan topping and marshmallows right before baking.
- Feeds a crowd. This casserole makes about 12 servings.
- Simple sweet potato base. No eggs or extra mix-ins here, just sweet potatoes, butter, brown sugar, and cinnamon.
- Need it nut-free? Leave out the pecans and use a crunchy topping such as crushed pretzels or graham crackers instead. The texture will be different, but you’ll still get a nice contrast with the soft sweet potato filling and marshmallows.
If you’re planning the full Thanksgiving spread, you can pair it with sausage apple stuffing muffins, mini cranberry brie bites, and honey maple roasted carrots.
Sweet Potato Casserole with Marshmallows and Pecans
Ingredients
- 3 sweet potatoes
- ½ cup + 1 tablespoon unsalted butter (130 g), cut into cubes
- 1 cup packed brown sugar (200 g)
- 1 teaspoon ground cinnamon
- ¼ cup unsalted butter (60 g), melted
- ⅓ cup + 1 tablespoon packed brown sugar (80 g)
- 2 tablespoons + 2 teaspoons all-purpose flour (20 g)
- ½ teaspoon salt (3 g)
- 1 cup finely chopped pecans (120 g)
- 5.3 oz marshmallows (150 g)
- Butter or cooking spray for greasing the baking dish
Instructions
- Peel the sweet potatoes and cut them into fairly large, similar-size pieces.
- Place the sweet potatoes in a large saucepan and cover them with cold water. Bring to a boil and cook until very tender and easily pierced with a fork.
- Drain the potatoes well and transfer them to a large bowl while they’re still hot. Add the cubed butter and mash until soft and smooth. The heat from the potatoes will melt the butter as you mash.
- Add the brown sugar and cinnamon and mix until everything is well combined and there are no large pieces of sweet potato remaining.
- Grease a 9-inch (23 cm) round baking dish with butter or cooking spray. Spoon in the sweet potato mixture and smooth the top with a spatula.
- For the pecan topping, combine the melted butter, brown sugar, flour, and salt in a bowl.
- Stir in the chopped pecans until you have a moist, crumbly mixture.
- Sprinkle the pecan mixture evenly over the sweet potato filling.
- Arrange the marshmallows in a single layer over the pecan topping.
- Bake in a conventional oven preheated to 350°F (180°C) for 25–30 minutes, until the casserole is hot, the pecan topping is lightly golden, and the marshmallows are puffed and caramelized on top.
- Keep a close eye on the casserole during the last few minutes because the marshmallows can go from golden to VERY golden quickly.
- Let the casserole rest for 5–10 minutes before serving. Serve hot or warm.
Notes
- Watch those marshmallows near the end. Once they start browning, they can darken quickly, so check the casserole frequently during the last few minutes.
- Drain the sweet potatoes really well. Extra water can make the filling looser instead of thick and creamy.
- Mash while they’re hot. This helps the butter melt straight into the potatoes and makes the filling easier to get smooth.
How to Make Sweet Potato Casserole
This one is pretty simple once the sweet potatoes are cooked, and the topping comes together fast. Don’t forget to check the full ingredient amounts and exact measurements in the recipe card above.
Gather all of your ingredients.
Cook the sweet potatoes. Peel and cut them into fairly large pieces, then boil until they’re very tender. You want a fork to slide in easily so the filling turns smooth instead of chunky.
Mash while they’re hot. Drain the sweet potatoes really well, then add the butter while they’re still hot. Mash until smooth and let the heat melt that butter right in.
Add the sugar and cinnamon. Stir in the brown sugar and cinnamon until everything is evenly mixed. At this point, the filling should be soft, smooth, and already smelling so good haha.
Fill the baking dish. Grease a 9-inch round baking dish, spoon in the sweet potato mixture and smooth the top with a spatula.
Make the pecan topping. Mix the melted butter, brown sugar, flour, and salt, then stir in the chopped pecans. You’re looking for a moist crumbly mixture, not something completely smooth.
Add the pecans. Spread the pecan mixture evenly over the sweet potato layer so you get that little bit of crunch in every serving.
Top with marshmallows. Arrange the marshmallows in a single layer over the pecans. Try not to pile them up too much or the top can brown before the center is fully hot.
Bake until golden. Bake at 350°F for 25–30 minutes, until the casserole is hot and the marshmallows are puffed and caramelized. Keep an eye on it near the end because marshmallows can go from golden to dark fast.
Let it rest. Give the casserole 5–10 minutes before serving. It’ll still be warm, but the layers will settle a little and scoop more cleanly.
I’m always watching that marshmallow layer like a hawk during the last few minutes because there’s a very fine line between beautifully toasted and well… that got away from me haha.
Storage and Make-Ahead
Make ahead: The day before Thanksgiving, you can boil and mash the sweet potatoes, then refrigerate them until you’re ready to assemble the casserole. You can also prepare the full sweet potato filling ahead and keep it covered in the baking dish. Add the pecan topping and marshmallows right before baking.
Store leftovers: Keep leftover casserole covered or in an airtight container in the refrigerator for up to 3–4 days.
Reheat: Warm individual servings in the microwave. For a larger portion, use a 350°F oven until heated through. Cover loosely with foil if the marshmallows start getting too dark.
Freezing: For the best texture, freeze the sweet potato filling without the marshmallows. Thaw it overnight in the refrigerator, then finish the casserole with the topping before baking.
More Holiday Recipes
Planning more than just Thanksgiving? Take a look through my holiday recipes for more easy ideas for Thanksgiving and Christmas.
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