The Absolute Best Sweet Potato Casserole with Marshmallows

I have a confession to make. For years, I thought I just wasn’t a sweet potato person. That is, until my mother-in-law slid a bubbling, golden-brown dish of this exact sweet potato casserole across the Thanksgiving table. One bite of that creamy, perfectly spiced filling topped with an impossibly gooey, toasted marshmallow crust, and I was hooked for life. Now, it is the single most requested side dish at every holiday gathering we host.

If you are looking for a side that feels like a warm hug, you have found it. This sweet potato casserole strikes that perfect balance between a savory dinner side and a borderline dessert. The real secret? We use sweetened condensed milk to give the sweet potatoes an ultra-velvety texture that you just can’t get with regular milk or heavy cream alone. Plus, it comes together so quickly, leaving you plenty of time to focus on the turkey or mingling with your guests. Whether it is your first time hosting Thanksgiving or you are just craving a comforting Sunday dinner side, I promise this recipe will earn a permanent spot in your recipe box.

What Is Sweet Potato Casserole?

If you didn’t grow up in the United States, you might be wondering why on earth we are putting marshmallows on a vegetable and serving it next to the roast turkey. Honestly, it is a fair question! Classic sweet potato casserole is a traditional American holiday side dish that beautifully blurs the line between sweet and savory.

At its core, this beloved dish consists of fresh sweet potatoes that are roasted or boiled until fork-tender, then mashed with rich butter, warm fall spices like cinnamon and nutmeg, and a sweetener. While some families swear by a crunchy brown sugar and pecan streusel topping, my heart belongs entirely to the marshmallow camp. As the casserole bakes, the marshmallows melt into a fluffy, sticky cloud with a perfectly toasted, caramelized top layer. It is a textural masterpiece. The creamy, earthy sweetness of the potato base perfectly complements the crispy, sugary bite of the marshmallows. It is nostalgic, decadent, and an absolute staple on Thanksgiving and Christmas tables across the country. Once you try it, you will completely understand the hype.

How to Make Sweet Potato Casserole

Quick Overview

Making this beloved sweet potato casserole is an absolute breeze. You will start by cooking your sweet potatoes until they are fall-apart tender. You can either boil them on the stovetop or bake them in the oven—whichever method you prefer! Once they are soft, you will mash them up with rich butter, sweetened condensed milk, and a cozy mix of fall spices. After spreading that smooth, fragrant mixture into a baking dish, you simply blanket the top with fluffy marshmallows and bake until golden and bubbly. It takes just about 25 minutes of hands-on prep time and 15 to 20 minutes in the oven.

Ingredients

You only need a handful of everyday ingredients to bring this magic to life:

• Sweet Potatoes: About 2.5 pounds. You can peel and cube them for boiling, or bake them whole and scoop out the flesh.
• Butter: 8 tablespoons (1 full stick) of unsalted butter, melted to add rich, savory depth.
• Sweetened Condensed Milk: 1 (14 oz) can. This is the star ingredient for the creamiest texture and perfect sweetness.
• Spices: 1 tablespoon of cinnamon and 1/2 teaspoon of nutmeg for that classic holiday warmth.
• Salt: Just 1/2 teaspoon to balance out the sweetness.
• Marshmallows: 1 (16 oz) bag. I love using the large, jumbo marshmallows, but mini marshmallows work wonderfully too!

Step-by-Step Instructions

Step 1: Preheat & Prep Pan

Begin by preheating your oven to 350°F. Grab a standard 9×13-inch glass casserole dish and lightly coat it with non-stick cooking spray so nothing sticks to the edges.

Step 2: Cook the Sweet Potatoes

If you are boiling: Peel and dice your sweet potatoes. Place them in a large stockpot, cover completely with water, and put the lid on. Bring to a boil and cook for about 15 minutes until they are easily pierced with a fork. Drain the water completely and return the potatoes to the pot. (If baking: roast them whole until soft, then peel and place the flesh in a large bowl).

Step 3: Mash and Mix

To your warm sweet potatoes, add the melted butter, sweetened condensed milk, cinnamon, nutmeg, and salt. Grab your potato masher and mash away until everything is beautifully combined, nice, and smooth.

Step 4: Assemble the Casserole

Transfer your spiced sweet potato mixture into your prepared 9×13 baking dish. Use a spatula to spread it out and smooth the top into a nice, even layer.

Step 5: Add Marshmallows and Bake

Line the entire top of the sweet potato casserole with your marshmallows. Pop the dish into your preheated oven and bake for 15 to 20 minutes. Keep a close eye on it toward the end—you want the marshmallows lightly toasted and puffed, not burnt! Serve warm and enjoy.

What to Serve It With

This sweet potato casserole is incredibly versatile and pairs beautifully with almost any hearty main course. Naturally, it is the star of the show on Thanksgiving, sitting proudly right next to a beautifully roasted turkey and a big bowl of homemade stuffing. The sweet and savory contrast is exactly what a traditional holiday plate needs.

If you are serving it for Christmas or Easter, it is absolutely phenomenal alongside a slow-cooker glazed ham. The saltiness of the ham and the sweet, creamy potatoes are a match made in heaven. For a regular Sunday family dinner, try serving it with roasted chicken, pork chops, or even a savory meatloaf. And do not forget your green veggies! A classic green bean casserole or some simple roasted Brussels sprouts will perfectly balance out the richness of this dish.

Top Tips for Perfecting Your Sweet Potato Casserole

Even though this recipe is incredibly straightforward, a few little tricks can take it from great to absolutely unforgettable.

• Baked vs. Boiled: While both methods work perfectly, baking your sweet potatoes whole in their skins actually retains more natural sweetness and keeps them from absorbing excess water. It makes the final mash a bit richer and more moist! Plus, you do not have to peel raw potatoes.
• Watch the Marshmallows: Marshmallows can go from beautifully toasted to totally burnt in a matter of seconds. Stay near the oven during the last few minutes of baking. If they do accidentally burn, do not panic! Just carefully scrape off the burnt layer completely, add fresh marshmallows, and toast again.
• Want a Lighter Texture? If you prefer a fluffier, airy sweet potato base rather than a dense and creamy one, try whipping one egg and folding it into the mashed sweet potato mixture before baking. It adds a gorgeous lift!
• Sweetener Substitutions: If you do not have sweetened condensed milk on hand, you can swap it out. Use a mix of dark or light brown sugar, or even pure maple syrup, along with a hearty splash of heavy cream or half-and-half. Taste as you go to get the sweetness just right.
• Using Canned Yams: In a pinch, you can absolutely use canned sweet potatoes. Just be sure to drain them incredibly well. Since they are usually packed in syrup, they are much sweeter than fresh potatoes, so sweeten slowly and taste as you mix.

Storing and Reheating Tips

If you are lucky enough to have leftovers of this sweet potato casserole, you will be thrilled to know it keeps wonderfully in the fridge. To store it, let the casserole cool completely to room temperature. Then, wrap the baking dish tightly with plastic wrap or transfer the leftovers into an airtight container. It will stay fresh in the refrigerator for up to 5 days.

When it comes to reheating, the oven is your best friend. Remove the plastic wrap, cover the dish loosely with aluminum foil (to prevent the marshmallows from burning), and warm it in a 350°F oven until heated through. Keep in mind that the marshmallows will melt down and evaporate a little bit when reheated. They won’t look quite as puffy and pristine as day one, but they will still taste incredibly gooey and delicious. If you are in a rush, you can also microwave individual portions in a microwave-safe dish, though the marshmallow texture will change.

Frequently Asked Questions

Final Thoughts

There is something so incredibly special about recipes that bring people together, and this sweet potato casserole does exactly that. The velvety, spiced sweet potatoes paired with that gooey, toasted marshmallow topping create a dish that feels like pure nostalgia in every single bite. It is sweet, comforting, and guaranteed to bring a smile to your family’s faces.

I really hope this recipe brings as much joy to your holiday table as it has to ours over the years. Don’t be surprised when your guests ask you for the recipe before dessert is even served! If you decide to give it a try, I would love to hear how it turns out for you. Happy cooking, and enjoy every delicious bite!

Easy Sweet Potato Casserole with Marshmallows

This impressive, but easy sweet potato casserole with marshmallows is a favorite family recipe that is easy to make with just a few simple ingredients. It’s so good you will want a second helping!

Prep : 10 Total : 25 minutes

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Ingredients

  

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Main Ingredients

• 2.5 lbs sweet potatoes peeled and diced, or baked and peels removed
• 8 tablespoons unsalted butter melted, 1 stick
• 1 can sweetened condensed milk 14 oz
• 1 tablespoon cinnamon
• 0.5 teaspoon nutmeg
• 0.5 teaspoon salt
• 1 bag large marshmallows 16 oz, or mini marshmallows

Instructions

 

Preparation Steps

• Preheat oven to 350°F. Spray a 9x13 casserole dish with non stick spray and set aside.
• In a large stock pot, add sweet potatoes and cover with water. Cover pot with lid, bring to a boil and cook until fork tender, about 15 minutes.
• Drain potatoes and transfer back to pot. Add butter, sweetened condensed milk, cinnamon, nutmeg and salt. Mash away until nice and smooth.
• Transfer the sweet potato mixture into the prepared baking dish and smooth out the top into an even layer.
• Line the top of the casserole with marshmallows and bake until marshmallows are lightly toasted, about 15 to 20 minutes.

Notes

Store any leftovers in an airtight container in the refrigerator for up to 4 days.