This recipe for Sweet Potato Casserole with Marshmallow Streusel Topping is rich and flavorful. It’s topped with a delicious crunchy streusel topping and toasted and gooey mini marshmallows, making for the best Thanksgiving side dish!
Sweet Potato Casserole is a classic at Thanksgiving for a reason! It tastes amazing and is a must-serve side dish. This Sweet Potato Casserole with Marshmallow Streusel Topping is going to become your new favorite! Not only does it have toasty, gooey, puffy marshmallows sprinkled throughout, but it also has a tasty streusel topping! You really can’t get better than this.
The sweet potato casserole is rich, creamy, and ultra flavorful! I tested this recipe with different ingredients and amounts and have perfected it. Sweet Potatoes are mashed along with butter, heavy cream, brown sugar, vanilla extract, salt, and eggs. Then topped with a yummy streusel. Once baked you can choose how many mini marshmallows to sprinkle on top or even just add it to half of the sweet potato casserole if your family is a little picky like mine! It’s easy to customize this recipe.
Do you vote that the streusel or marshmallows are the best part? It’s hard to choose! Thank goodness with this Sweet Potato Casserole you don’t have to choose.
To make the streusel for the sweet potato casserole:
Mix together:
- flour
- brown sugar
- melted butter
- oats (or pecans)
- salt
- and cinnamon
How to Make Sweet Potato Casserole with Marshmallow Streusel Topping:
First- Boil the sweet potatoes (or if you’d prefer to roast them, follow the instructions for that here.)
Second- While it’s boiling mix together the ingredients for the streusel.
Third- Once the sweet potatoes are tender drain and mash them. Mix in butter, heavy cream, brown sugar, vanilla, salt, and then 2 eggs.
Fourth- Tranfer to a 9×13 pan, top with streusel, and bake for 25 minutes.
Last step! Pull it out of the oven and sprinkle on 2-3 cups of mini marshmallows. Stick it back in the oven for 5-7 minutes. Let cool slightly, serve, and enjoy!
Why this Sweet Potato Casserole is so great and tips!
After testing this recipe many times I chose to use heavy cream instead of milk. With the marshmallow topping, this side dish is more dessert-like. So adding heavy cream gives it a rich and deep flavor. I also add a little more vanilla extract than most recipes. You will love the flavor!
Not only is the sweet potato casserole delicious, but the streusel is also incredible! I chose to add some oats to give it more of a crunch but honestly, the streusel is quite flexible. You can instead add pecans or even add both. (Just add about 3 tablespoons of each or so.)
Then to really make this Sweet Potato Casserole magical, a beautiful shower of mini marshmallows is sprinkled on top! In the recipe, I say to add 2-3 cups. The pictures you see on this post show 2 cups because I wanted you to be able to see the streusel topping. I personally think adding 3 cups would be amazing! But do as you please. You can just put marshmallows on half or stripe it throughout or even not add them. Whatever makes you and those you serve this to happy!
Enjoy!
For more tips and tricks as well as make-ahead tips please check out this post.
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* * THE BEST THANKSGIVING RECIPES! * *
Sweet Potato Casserole with Marshmallow Streusel Topping

This recipe for Sweet Potato Casserole with Marshmallow Streusel Topping is rich and flavorful. It's topped with a delicious crunchy streusel topping and toasted and gooey mini marshmallows, making for the best Thanksgiving side dish!
Ingredients
FOR THE SWEET POTATOES:
- 3 pounds sweet potatoes
- 1/3 cup butter, softened
- 1/3 cup heavy cream
- 1/2 cup brown sugar
- 2 teaspoons vanilla extract
- 1/2 tsp salt
- 2 eggs
MARSHMALLOW STREUSEL TOPPING:
- ½ cup all-purpose flour
- 2/3 cup brown sugar, packed
- 1/3 cup unsalted butter, melted
- 1/3 cup oats (or chopped pecans)
- ¼ teaspoon kosher salt
- ½ teaspoon cinnamon
- 2-3 cups mini marshmallows
Instructions
1. Peel sweet potatoes. Dice into 1-inch cubes. Add to a large pot of salted water. Bring to a boil over high heat, then lower the heat to a simmer and cook until the potatoes are tender about 15-20 minutes.
2. Drain sweet potatoes. Using a potato masher, mash well so that there are no big chunks.
3. Add softened butter, heavy cream, brown sugar, vanilla, and salt. Mix by hand or for a smoother texture, with a hand mixer or electric mixer. Stir until completely combined then mix in eggs until incorporated.
4. Preheat the oven to 350 degrees. Butter or grease a 9x13 inch baking dish and transfer the sweet potato mixture to the dish.
5. For the topping, in a medium bowl, combine all topping ingredients: flour, brown sugar, melted butter, oats, salt, and cinnamon. Sprinkle half of the streusel evenly over the casserole.
6. Bake for 25 minutes at 350 degrees, until set in the middle and golden on top. Top with 2-3 cups of mini marshmallows and bake for another 5-7 minutes, until the marshmallows are lightly brown and puffy.
7. Serve warm.
This is going to be so delicious for thanksgiving! 🙂 I can’t wait! YUM!
It was a hit!