Sweet Potato Casserole with Pecans & Marshmallows

Sweet Potato Casserole is a classic Thanksgiving side dish made with creamy, buttery sweet potatoes, brown sugar, crunchy pecan streusel, and gooey toasted marshmallows. It’s sweet enough to almost count as dessert, but somehow it belongs right next to the turkey and stuffing!

One thing I had to get used to when I moved to the US was the idea of putting marshmallows on sweet potatoes. Growing up in New Zealand, that definitely wasn’t something we put on the dinner table! I’ve come to appreciate how the creamy sweet potatoes, buttery pecan topping, and toasted marshmallows all work together. It’s a proper American holiday side dish, and one I’m happy to make.

For a savory spin on sweet potatoes, try my baked sweet potato wedges – they’re crispy outside, fluffy inside, and go with anything. For another decadent side, try Mississippi Mud Potatoes!

Step-by-step photos and instructions are below. Jump to the recipe card if you wish!

Why you’ll love this

This Sweet Potato Casserole is easy to make, full of flavor, and always a welcome addition to the holiday table. And yes, we’re putting marshmallows on vegetables.

• The best of both worlds. Creamy, buttery sweet potatoes topped with crunchy pecan streusel and gooey, toasted marshmallows.
• Easy to make. Simple ingredients and straightforward steps. You can prepare the topping while the sweet potatoes cook.
• Make-ahead friendly. Prepare the sweet potato filling ahead of time, then add the toppings and bake when you’re ready.
• Perfect for the holidays. A classic side dish for Thanksgiving or Christmas that goes beautifully with turkey, ham, and all your favorite holiday sides.
• A little something for everyone. You get both pecan streusel and marshmallows, so there’s no need to choose between the two!

About this Sweet Potato Casserole Recipe

This recipe starts with fresh sweet potatoes, peeled, diced, and boiled until tender. They’re mashed with butter, half and half, brown sugar, salt, and pumpkin pie spice to make a smooth, creamy filling.

Then comes the good stuff! A buttery pecan streusel made with brown sugar, flour, cinnamon, and chopped pecans, plus plenty of mini marshmallows. You get a little crunch from the pecans, gooey marshmallows, and creamy sweet potatoes in every bite.

The casserole goes into the oven just long enough for the marshmallows to turn golden and the topping to get lightly browned. Since the sweet potatoes are already cooked, there’s no need for a long baking time.

I’ve included step-by-step photos below, along with tips for making the casserole ahead of time, which is especially handy when you’re preparing Thanksgiving dinner.

Making Ahead

This is a great recipe to prepare ahead of Thanksgiving or Christmas dinner.

Make the sweet potato filling, spread it into an 8×8-inch baking dish, cover, and refrigerate for up to 2 days. Keep the pecan streusel and marshmallows separate until you’re ready to bake.

When it’s time to serve, preheat the oven to 350°F (177°C). Cover the baking dish with foil and warm the sweet potato filling for about 20-25 minutes, or until heated through. Remove the foil, add the pecan streusel and marshmallows, then increase the oven temperature to 375°F (190°C). Bake for another 7-10 minutes, until the marshmallows are golden and the topping is lightly browned.

Slow cooker option: You can also keep the prepared sweet potatoes warm in a slow cooker on the warm setting. Add the toppings shortly before serving, but remember that the marshmallows will melt rather than toast, and the streusel won’t get crispy.

Want more thanksgiving recipes? Check out this Easy Stuffing Recipe, or this Green Bean Casserole from Scratch.

Step-by-step photos and tips and tricks are below. Jump to the full recipe card instead

• Sweet potatoes. Use fresh sweet potatoes, peeled and cut into evenly sized pieces so they cook at the same rate. Cook until very tender for a smooth filling.
• Butter and salt. Butter adds richness to both the sweet potato filling and pecan streusel, while salt balances the sweetness.
• Brown sugar. Adds sweetness to the filling and helps make the pecan streusel crumbly. Light or dark brown sugar will work.
• Half and half. Makes the sweet potato filling creamy. Whole milk or heavy cream can also be used.
• Pumpkin pie spice and cinnamon. Pumpkin pie spice flavors the filling, while cinnamon adds warmth to the streusel. You can use cinnamon in place of pumpkin pie spice, or make your own Pumpkin Pie Spice.
• Pecans and flour. Chopped pecans add crunch, while all-purpose flour helps create the crumbly streusel topping.
• Mini marshmallows. These toast until golden and gooey. Mini marshmallows are easier to spread evenly over the casserole than large ones.

Prepare the sweet potatoes and pecan topping

Cook the sweet potatoes: Peel and cut the sweet potatoes into small, evenly sized pieces. Place them in a large pot and cover with about an inch of cold water. Bring to a boil, then simmer for 15-20 minutes, until very soft and easily pierced with a fork.

Make the pecan streusel: While the potatoes cook, combine the butter, brown sugar, flour, cinnamon, salt, and chopped pecans in a bowl. Mix until crumbly, with small buttery clumps throughout.

Make the sweet potato filling

Mash the sweet potatoes: Drain the cooked sweet potatoes well and return them to the pot. Mash until most of the lumps are gone.

Make the filling: Add the butter, half and half, brown sugar, pumpkin pie spice, and salt. Continue mashing and mixing until the filling is smooth and creamy. You can use a hand mixer if you prefer a smoother texture.

Assemble the casserole

Spread the filling: Transfer the sweet potato mixture to an 8×8-inch baking dish and spread it into an even layer.

Add the toppings: Scatter half the mini marshmallows over the sweet potatoes, then sprinkle the pecan streusel evenly over them. Finish with the remaining marshmallows so you can see both the streusel and marshmallows on top.

Bake the casserole

Bake at 375°F (190°C) for 7-10 minutes, until the marshmallows are golden and the pecan topping is lightly browned. Keep an eye on it toward the end, because marshmallows can burn quickly!

FAQs

More recipes to love

• Easy Scalloped Potatoes – there’s a video on this one, showing how EASY this is to make!
• Pan Roasted Brussels Sprouts – Roasted Brussels sprouts, paired with delicate shallots, salty bacon and a bit of parmesan – YES PLEASE
• Bacon Wrapped Green Beans. The BEST side for holidays! Fresh green bean bundles are easy to grab and soon to be family favorite!
• Glazed Carrots. A simple side dish, using the sweetness of brown sugar combined with fresh rosemary. These Rosemary Glazed Carrots are great for holidays or just a regular Tuesday!
• Sauteed Green Beans. Garlic and shallots gently flavor these sautéed green beans making them a wonderful weeknight or holiday side dish!
• Red Lobster Biscuits. Soft, fluffy biscuits packed with cheddar cheese, and brushed with flavorful garlic butter after baking, these cheddar biscuits are dreamy!
• ALL SIDES

5 from 4 votes

Sweet Potato Casserole with Marshmallow and Pecans

Author Kylee Ayotte

Servings 8

Prep Time: 10 minutes mins

Cook Time: 30 minutes mins

Total Time: 40 minutes mins

Print

Pin

Rate

Sweet Potato Casserole is a wonderful combination of sweet potatoes, brown sugar, and an ooey-gooey topping of marshmallows and pecan streusel!

Cook ModePrevent your screen from going dark

Equipment

• 8 x 8" baking dish
• Potato masher

Ingredients

 

1x2x3x

Sweet Potatoes

• ▢ 2.5 pound sweet potatoes
• ▢ 2 tablespoons butter
• ▢ ½ cup half & half
• ▢ ½ teaspoons pumpkin pie spice
• ▢ ¼ cup brown sugar packed
• ▢ salt

Topping

• ▢ 4 tablespoons butter
• ▢ 1/2 cup brown sugar packed
• ▢ 1/2 cup all-purpose flour
• ▢ 1 teaspoon cinnamon
• ▢ Pinch salt
• ▢ ½ cup chopped pecans
• ▢ 3 cups mini marshmallows

Instructions

For the sweet potatoes

• Peel and chop 2.5 pound sweet potatoes into small pieces.
• Add to a large pot, and cover with about an inch of cold water. Bring to a boil, and simmer for 15-20 minutes until very soft.
• Drain the and return sweet potatoes to the pot. Mash lightly.
• Add 2 tablespoons butter, ½ cup half & half,½ teaspoons pumpkin pie spice, ¼ cup brown sugar and salt to the potatoes.
• Continue mashing until smooth.
• Transfer the sweet potatoes to an 8×8 casserole dish and keep warm if serving right away.

Topping

• If you bought whole pecans, chop them into small pieces.
• In a small bowl, combine 4 tablespoons butter, 1/2 cup brown sugar, 1/2 cup all-purpose flour, 1 teaspoon cinnamon, Pinch salt and ½ cup chopped pecans until thoroughly combined. See pic for texture.

Assemble/Bake

• Top with half the 3 cups mini marshmallows, then sprinkle the streusel over the marshmallows. Top with the other half of the marshmallows. You should be able to see both marshmallow and streusel.
• Bake at 375°F for 7-10 minutes, until the topping is bubbly and brown (keep an eye on it so the marshmallows don't burn).
• Devour.

Video

Notes

While you make the topping, preheat oven to 375°F.

Heat your liquid (half and half, cream, milk). Hot milk is better than cold, as it will keep your potatoes piping hot!

Boiling sweet potatoes will take less time if you cut them into smaller chunks.

How to tell if my sweet potatoes are cooked properly?

You’ll know they are cooked if you can mash one against the side of the pot. You can use a knife or fork, too. They need to be soft all the way through (or you’ll have lumps!)

What do do with leftovers

Store in a covered container in the refrigerator for up to 4 days. Reheat until piping hot!

Substitutions/Additions

• You can use milk, sour cream or greek yogurt instead of half and half. Heavy cream can also be used.
• You can sub cinnamon for pumpkin pie spice if you don’t have it. But if you want to make your own pumpkin pie spice, I got you!

Making ahead

If you are making these for a holiday – you can make them ahead. Simply pour the mashed sweet potatoes into an 8×8 baking dish, and cover. Refrigerate. Heat the casserole in the oven until the sweet potatoes are warm, then add the topping and bake for 10-15 minutes, until the topping is bubbly and brown (keep an eye on it so the marshmallows don’t burn).

A crock pot/slow cooker will also keep these warm if you make them earlier in the day, but the topping won’t brown (just melt).

⭐️ Don’t Forget! I love to hear how this turned out for you! Share your thoughts by leaving a review and rating below.

Would you like to save this recipe?

We’ll email this post to you, so you can come back to it later!

Nutrition

Calories: 433kcal | Carbohydrates: 72g | Protein: 5g | Fat: 15g | Saturated Fat: 7g | Cholesterol: 28mg | Sodium: 181mg | Potassium: 561mg | Fiber: 5g | Sugar: 37g | Vitamin A: 20429IU | Vitamin C: 4mg | Calcium: 85mg | Iron: 2mg

Nutritional information is an estimate and provided to you as a courtesy. You should calculate the nutritional information with the actual ingredients used in your recipe using your preferred nutrition calculator.

Sharing of this recipe is both encouraged and appreciated. Copying/pasting and/or screenshots of full recipes to any social media is strictly prohibited. Content and photographs are copyright protected.

Did you make this recipe?

Make sure to follow @kyleecooks on Instagram for more and tag me #kyleecooks so I can see!

About Kylee Ayotte

I am a born and raised New Zealander (a Kiwi), now living in Phoenix, Arizona. I’m happily married to the love of my life – a hot American boy I met while traveling the world. I’m a mama to 2 awesome little boys and love red things, rugby, cheesecake, and bacon. Mmmmm. Bacon. Meet Kylee