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Sweet Potato Casserole with Marshmallows and Pecan Streusel

Updated July 2, 2025 / By Holly Erickson & Natalie Mortimer

It’s not Thanksgiving dinner until there’s a sticky, rich, delicious pecan-and-marshallow topped sweet potato casserole baking in the oven. And our sweet potato casserole recipe is the best ever!

baked Homemade Sweet Potato Casserole with Marshmallows and Pecan Streusel in a baking dish being scooped with a wooden spoon

A Super Classic All-American Sweet Potato Casserole That’s Sweet as Can Be

Grandma knew a thing or two about what people really want on the table on Thanksgiving, and as much as we love recipes that bring a little freshness to the table, we’ve got a super soft spot in our junk-food loving hearts for classic, sticky, creamy, rich sweet potato casserole. And why is our sweet potato casserole recipe the best ever? Well, we pull NO punches and we haven’t modernized it in the slightest! We’ve got good old mini-marshmallows—layers of them—along with a fluffy, sweet, creamy sweet potato filing and a toasty, sweet pecan streusel topping that takes things way over the top in this is-it-a-dessert-or-is-it-a-side-dish recipe. To complete your Thanksgiving menu take a look at our 40 Best Thanksgiving Side Dishes.

ingredients for sweet potato casserole with marshmallows and pecan streusel in bowls on a counter

Sweet Potato Casserole Ingredients—Starting With Those Mini-Marshmallows!

We’re betting that the grocery list for this sweet potato casserole recipe is going to overlap a lot with all of the other ingredient lists you’ve got going for Thanksgiving. Warm, holiday baking spices, heavy cream, butter, pecans. You probably need those same things for making pies, mashed potatoes and, well, everything else that’s going on that heavily-laden holiday table! You can buy all of it way ahead of time, too, if you’re a super prepared person. Here’s everything you’ll need to make this classic, easy sweet potato casserole:

  • Sweet potatoes

  • Brown sugar

  • Maple syrup

  • Vanilla

  • Lemon

  • Heavy cream

  • Eggs

  • Cinnamon, ginger, nutmeg

  • Pecans

  • Mini marshmallows

  • Butter

  • Flour

melted butter, pecans, salt, brown sugar, flour and cinnamon in a mixing bowl on the counter
sweet potato casserole pecan streusel topping in a mixing bowl on the counter

Why Do Americans Put Marshmallows on Sweet Potato Casserole? A Brief History of Sweet Potato Casserole With Marshmallow Topping.

This is a fantastic question, because—even though many of us grew up eating sweet potato casserole with marshmallows on it—this is kind of an oddball recipe when you stop and think about it. Like a lot of oddball recipes, this one actually grew out of a marketing scheme! What else? Back in the early 1900s, a company called Angelus Marshmallows was trying to get Americans to eat more of their fluffy, squishy marshmallows and so they came up with a bunch of recipes that featured marshmallows, one of which was the now-classic, marshmallow-topped sweet potato casserole. You can read more about the history of this very American dish over on the Smithsonian’s website.

cubed cooked sweet potatoes in a large pot
mashed sweet potatoes in a large pot
mashed sweet potatoes, butter, brown sugar, maple syrup, vanilla, lemon juice, heavy cream, eggs and spices  in a large pot
uncooked sweet potato casserole in a baking dish

How To Make Sweet Potato Casserole with Marshmallows

Our sweet potato casserole recipe is designed to be easy, of course, but also to be the best sweet potato casserole recipe ever. So it’s easy, but it’s not open-a-few-cans easy. Because best is more important than easy on a day like Thanksgiving, right? So here’s how to make this traditional sweet potato casserole:

  1. Cook the sweet potatoes!

  2. Mix together the butter , salt, brown sugar, flour and cinnamon to make the streusel topping.

  3. Smash together the potatoes, butter, brown sugar, maple syrup, vanilla, lemon juice, heavy cream, salt, eggs, nutmeg, cinnamon and ginger to make the filling!

  4. Spread the sweet potato mixture in a baking dish.

  5. Top it with marshmallows, streusel, pecans and more mini-marshmallows.

  6. Bake! It’ll take about 30 minutes.

unbaked sweet potato casserole topped with marshmallows
unbaked sweet potato casserole topped with marshmallows and pecan streusel topping

Thanksgiving Game Plan: Make Your Sweet Potato Casserole Ahead of Time!

One of the best things about sweet potato casserole is that you can make it ahead of time! Simply make it all the way through to the point of baking, and stop right before you’d put it in the oven. Then, cover your sweet potato casserole with foil and store it in the refrigerator for up to 24 hours. When you’re ready to bake it, pull it out of the oven and let it come to room temperature. Then pop it in a preheated oven and bake! Yay for anything you can do ahead of time on the oven-and-stove juggle that is Thanksgiving Day! Unfortunately, this sweet potato casserole doesn’t freeze well.

baked Homemade Sweet Potato Casserole with Marshmallows and Pecan Streusel in a baking dish
baked Homemade Sweet Potato Casserole with Marshmallows and Pecan Streusel in a baking dish

More Sweet Potato Recipes for your Thanksgiving Table

Tools You’ll Need

baked Homemade Sweet Potato Casserole with Marshmallows and Pecan Streusel in a baking dish
baked Homemade Sweet Potato Casserole with Marshmallows and Pecan Streusel in a baking dish being scooped with a wooden spoon

Happy Holidays!

It’s the most wonderful time of year to get into the kitchen with your loved ones and get cooking! We hope this sweet potato casserole recipe is exactly what you’re looking for. When you try it, we’d love to hear about it! Share a photo and tag us on Instagram using @themodernproper and #themodernproper so that we can see your stuff! Happy eating!

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Sweet Potato Casserole with Marshmallows and Pecan Streusel Recipe

  • Serves:  10
  • Prep Time:  25 min
  • Cook Time:  45 min
  • Calories:  368

Description

It’s not Thanksgiving dinner until there’s a sticky, rich, delicious pecan-and-marshallow topped sweet potato casserole baking in the oven. And our sweet potato casserole recipe is the best ever!

Ingredients

  • 3 ¼ teaspoons sea salt
  • 3 pounds sweet potatoes, (about 3 to 4 large), peeled and cut into 2-inch pieces
  • ½ cup unsalted butter, melted
  • ⅔ cup light brown sugar
  • ⅓ cup all-purpose flour
  • 1 teaspoon cinnamon
  • 2 tablespoons maple syrup
  • 1 teaspoon vanilla extract
  • 1 tablespoon fresh lemon juice, (from 1 lemon)
  • ¼ cup heavy cream
  • 2 large eggs
  • ⅛ teaspoon nutmeg
  • ¼ teaspoon ginger
  • 2 cups mini marshmallows
  • ⅓ cup chopped pecans

Method

  1. Preheat the oven to 350°F with a rack in the center position. Grease a 9 x 13-inch baking dish.

  2. Bring a large pot of water and 2 teaspoons of the salt to a boil over high heat. Add the sweet potatoes and simmer until fork-tender, about 15 minutes.

  3. Meanwhile, make the streusel topping. In a small bowl, mix together ¼ cup of the melted butter, ¼ teaspoon of the salt, ⅓ cup of the brown sugar, the flour, and ½ teaspoon of the cinnamon until combined. Use your fingers to press the mixture together until pea-size pieces are formed. Refrigerate while you prepare the other ingredients.

  4. Drain the sweet potatoes and return them to the pot. Using a potato ricer or masher, mash the cooked sweet potatoes together with the remaining 1 teaspoon salt, the remaining ¼ cup melted butter, remaining ⅓ cup brown sugar, remaining ½ teaspoon cinnamon, maple syrup, vanilla, lemon juice, heavy cream, eggs, nutmeg, and ginger, until smooth.

  5. Spread the sweet potato mixture evenly into the prepared baking dish. Top with 1½ cups of the marshmallows, then crumble the streusel topping over the marshmallows. Sprinkle with the pecans and the remaining ½ cup marshmallows.  

  6. Bake for 25 to 30 minutes, until the marshmallow topping is golden brown. If the marshmallows brown too quickly, cover with foil. Let sit for 5 minutes before serving.

Notes

To make this casserole ahead, stop after step 5, cover with foil, and refrigerate for up to 24 hours. Bring to room temperature before proceeding with step 6.

Nutrition Info

  • Per Serving
  • Amount
  • Calories 368
  • Protein 4 g
  • Carbohydrates 61 g
  • Total Fat 12 g
  • Dietary Fiber 5 g
  • Cholesterol 61 mg
  • Sodium 860 mg
  • Total Sugars 18 g

Sweet Potato Casserole with Marshmallows and Pecan Streusel

Questions & Reviews

Rated 5 stars by 3 readers

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  • Mary

    What can you replace the heavy cream with? Something lighter in calories.

    You can use whatever kind of milk you have on time. The heavy cream just adds a nice texture.

  • Pamela

    Why do you have eggs in the mixture?

    Eggs make the casserole light and fluffy.

  • Myra

    To serve Sunday at 1pm, could I make this on Friday NIGHT and refrigerate until Sunday? (more than the recommended 24 hrs?)

    Sure! I would keep the pecan streusel separate until you are ready to bake it.

  • Rachel

    The big hit of our Thanksgiving table, literally not a spoonful left 😆 a perfect mix of ingredients that left normal sweet potato skeptics happy!

    YAY! So happy everyone enjoyed them!

  • Rachael

    This was fabulous! Everyone loved it and a few people asked for the recipe. The last few years, I've made healthier versions of sweet potato casserole and none of them really wowed, so I decided to go for the marshmallows and sugar this year. And it. was. worth it! Will be making this every year!

    That is so exciting to hear. Thanks Rachael, so glad you loved these!

  • Jenn

    Best sweet potato casserole I've ever made, new go to for thanksgiving!

    Yay! Thank you Jenn!