Sweet Potato Casserole is the perfect make ahead side dish for festive holiday meals or low-key weekday dinners. Creamy, buttery sweet potatoes are baked with a crunchy marshmallow streusel topping for a delicious side dish.
You might also like Sausage Breakfast Casserole and Banana French Toast Casserole.
The Best Sweet Potato Casserole Side Dish
Packed with flavor and easy to adapt, this homemade sweet potato casserole is so creamy, with custard-like filling and irresistible crunchy cinnamon crumble on top. Did I mention toasted marshmallow topping? Boston Market restaurant chain uses marshmallows on their signature sweet potato side dish all year long and so do I:)!
This recipe also incredibly easy to prepare ahead of time, making it perfect for busy holiday cooking schedules.
A reader, Skimamama, says: "Turned out great. Several people liked this more than the traditional brown sugar pecan topping. This has just the right amount of sweetness. It's a keeper for sure." ★★★★★
Key Ingredients
- Sweet potatoes (sometimes confusingly labeled as yams in stores) are the star for their naturally sweet, creamy texture.
- Egg: It's optional, but if you want more structure in your casserole, definitely add 1 small egg.
- Brown sugar: Using brown sugar in both the filling and the topping deepens the flavor and brings a hint of caramel.
- Butter: Unsalted is best for control. Butter adds richness and moisture, Heavy Cream: Creates a smooth mash that won't dry out in the oven.
- Vanilla extract enhances all the sweet flavors.
- Topping: For the perfect crumble, brown sugar, flour, cinnamon, cooled melted butter form a nutty, golden streusel that bakes up crisp and toasty.
How to Make Sweet Potato Casserole
This is an overview with step-by-step photos. Full ingredients, measurements & instructions are in the recipe card below.
1. Prepare Sweet Potatoes
- Peel and cut sweet potatoes into even pieces. Boil until fork-tender, then drain completely.
- Mash and Flavor: While still warm, mash sweet potatoes until mostly smooth. Add butter, brown sugar, salt, vanilla, cinnamon, and nutmeg, incorporating everything thoroughly for a uniform mixture.
- Stir in heavy cream to achieve that ultra-creamy consistency-it's the secret for restaurant-quality results.
- Transfer to Baking Dish: Spread the sweet potato mixture evenly in a baking dish.
- Top with Marshmallows: Cover the surface with mini marshmallows for best melt and color.
2. Make Cinnamon Streusel
- Combine flour, cinnamon, brown sugar, and butter. Use your fingers or a fork-stop mixing as soon as clumps form. If mixture seems too dry, add a drop of water; if too doughy, increase flour or sugar.
- Add Streusel: Sprinkle the streusel generously over the marshmallows.
3. Bake
Bake until marshmallows are golden and the center is warmed through.
Sweet Potato Casserole
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Ingredients
Sweet Potatoes
- 5 pounds sweet potatoes (peeled and cut into 1" pieces)
- 4 tablespoons unsalted butter (½ stick)
- ½ cup brown sugar
- ½ teaspoon salt
- 1 teaspoon pure vanilla extract
- 1.5 teaspoon ground cinnamon
- ¼ teaspoon ground nutmeg
- ½ cup heavy cream
- 1 small egg optional, but helps the structure
- 2 cups mini marshmallows
Brown Sugar Streusel Topping
- 1 cup all-purpose flour
- ¼ teaspoon salt
- 1 teaspoon ground cinnamon
- 6 tablespoon unsalted butter room temperature
- ¼ cup dark brown sugar (packed)
Instructions
Streusel Topping
- Mix flour, salt, ground cinnamon, butter and dark brown sugar with a fork until a desired crumble texture is achieved. Add more sugar if you want finer crumbs.
Sweet Potatoes
- Bring large pot with water to boil over high heat. Add sweet potato pieces and cook until fork tender, about 15 to 20 minutes.
- Drain potatoes and place them back into pot or large bowl. Mash potatoes with a potato masher or blend with an electric mixer, until mostly smooth.
- Add butter, brown sugar, salt, vanilla extract, nutmeg and cinnamon and combine
- Add heavy cream and 1 small egg (optional), combine for another minute until well incorporated.
- Transfer sweet-potato mixture to a 2-quart baking dish. Top with 2 cups of mini marshmallows and set aside.
- Preheat oven to 375 F.
Final Assembly
- Top the sweet potato mixture and marshmallows with the prepared crumble topping.
- Bake at 375F until center is warmed through and marshmallows and topping is lightly browned, 30 minutes.
Why is my sweet potato casserole watery or runny?
Large sweet potatoes can be more fibrous and watery; opt for small or medium potatoes for a creamier, less runny result.
- Drain boiled sweet potatoes thoroughly; excess moisture leads to soggy filling.
- Optional: Add 1 small egg (for structure) and use a hand mixer-this breaks up fibers, creating a smoother, less watery casserole.
- If your filling still seems loose, mix in a tablespoon of flour or cornstarch before baking.
How do I fix a bland sweet potato casserole?
- Boost flavor by adding extra vanilla, cinnamon, or brown sugar to the potato mixture.
- Try roasted sweet potatoes instead of boiled-they become caramelized and richer in taste.
- Swap some regular sugar with dark brown sugar or maple syrup for increased depth.
What if the topping melts into a paste instead of forming a crumble?
- Don't melt butter before adding it to the brown sugar and flour-hot butter will dissolve the sugar and ruin the streusel texture.
- Let the butter rest at room temperature for 10 minutes before mixing with the topping ingredients.
Pro Tips for the Best Sweet Potato Casserole
- For a sweeter, less stringy filling, choose small to medium sweet potatoes-large ones can be fibrous and watery.
- For super smooth texture, use a hand mixer. Unlike regular potatoes, sweet potatoes won't turn gummy with mixing-they actually get creamier.
- If your casserole comes out watery, double-check for excess water in your potatoes after boiling. Always drain and let steam dry before mashing.
- To avoid a runny filling, don't skip the optional egg-if you need an egg-free option, be aware the texture will be looser.
Frequently Asked Questions
Can I use white or purple sweet potatoes?
Both work, but these tend to be drier than orange sweet potatoes. Use extra milk to keep them creamy.
Can I use maple syrup in place of brown sugar?
In the filling, yes; in the topping, no. Maple syrup will not yield a crumbly topping texture-it becomes a paste, so stick with brown sugar for the streusel.
Is this recipe good for making ahead and freezing?
Definitely! Assemble, wrap tightly, and freeze unbaked for up to three months. Thaw overnight and bake topped with fresh pecan streusel or marshmallows.
Substitutions and Variations
Can I use canned sweet potatoes?
Yes, but only canned sweet potatoes packed in water-not syrup. Drain extremely well to avoid excess moisture.
Skip candied yams because the casserole will be too sweet and possibly mushy.
Can sweet potato casserole be made vegan or gluten-free?
Replace milk with any non-dairy alternative, use vegan butter, and skip or replace eggs with flax eggs for binding.
Choose your favorite gluten-free flour blend for the topping-cassava flour works well, as confirmed by user reviews.
What's a good substitute for brown sugar or flour in the topping?
Use coconut sugar instead of brown sugar for a less processed option. Substitute flour with almond, oat, or cassava flour for gluten-free needs.
Serving Suggestions
- Pairs beautifully with roasted Herb and Citrus Roasted Turkey, Beer Braised Lamb Shanks, Roasted Spatchcock Chicken, or vegetarian mains, such as Marry Me Butter Beans.
- Excellent side dish for Thanksgiving, Christmas, or potlucks-and surprisingly popular for Sunday brunch.
- Garnish with a sprinkle of cinnamon or Balsamic glaze for added color.
Storage and Leftovers
- Refrigerate: Store leftovers in an airtight container for up to 4 days.
- Reheat: Place in the oven at 350°F until heated through, or use microwave for single servings.
- Freeze: Sweet potato casserole (without marshmallow topping) can be frozen for up to 3 months; thaw overnight and add marshmallows before reheating.
Tiara says
I'm curious as to why the streusel topping can't be made the night before
Olya says
Yes, you can and keep in an airtight container in the refrigerator until ready for use.
Jess says
So excited to try this recipe! Is there a way to substitute the heavy cream?
Olya says
You can use half and half.
Faith says
Would there be a way to substitute canned yams for the sweet potatoes? Do you know how much yams you would use? I am cooking everything myself this year, so looking to make it a little easier.
Olya says
Yes, of course!
Jen says
Hands down the best sweet potato dish I have ever had. Everyone at my Thanksgiving table agreed—even the people who don’t like sweet potatoes loved this!
Olya says
So glaaaad it was the best sweet potato dish at your table!!!
Christina says
Can I make it the day before and just add the toppings the next day and pop in the oven?
Olga says
Yes, it would be perfectly fine
Laura says
Can bananas be incorporated in this dish
Olga says
Yes!
Julio says
How many people does this serve?
Olga says
Six large servings.
Johnny says
I thought that sweet potatoes needed more sugar. Other than that, I liked it.
Fiona says
I tried it exactly as the recipe - it reminded me of Boston Market's sweet potatoes. Very good.
Valerie says
I added pecans into the topping, I chopped them pretty well and really loved it!