The Ultimate Sweet Potato Casserole with Marshmallows

Let’s be completely honest for a second—when the holidays roll around, the side dishes are the real stars of the show. Sure, the turkey gets a lot of the glory, but what are we actually piling high on our plates? For my family, it’s always this gooey, perfectly spiced sweet potato casserole. I swear, if I didn’t make this for Thanksgiving, there might be an actual mutiny at the dinner table!

There’s an ongoing debate in the food world about whether sweet potatoes belong with a crunchy pecan streusel or a thick blanket of toasted marshmallows. If you’re reading this, I’m guessing you’re proudly on Team Marshmallow, just like we are. This dish perfectly bridges that magical gap between a savory dinner side and an outright dessert. The smell of cinnamon and nutmeg wafting through the kitchen while this bakes is basically the official scent of the holidays.

Whether you’re hosting your very first Friendsgiving or you’ve been in charge of the family feast for decades, this easy sweet potato casserole is going to become your new secret weapon. Grab your favorite baking dish, and let’s get cooking!

What Is Sweet Potato Casserole?

If you didn’t grow up with this iconic dish, you might be wondering what exactly a sweet potato casserole is. At its core, it’s a traditional American holiday side dish that takes humble, earthy sweet potatoes and elevates them into something truly magical.

Imagine a base of freshly boiled or baked sweet potatoes, mashed until they’re incredibly smooth and velvety. But we don’t stop there. We blend those mashed potatoes with rich melted butter, warm fall spices like cinnamon and nutmeg, and a pinch of salt to balance everything out. The absolute game-changer in this specific recipe, though, is sweetened condensed milk. Instead of messing around with regular sugar and heavy cream, the condensed milk adds the perfect level of sweetness and an unbelievably creamy texture that you just can’t get any other way.

Finally, the whole glorious mixture is spread into a baking dish and generously crowned with large, fluffy marshmallows. As it bakes, the sweet potato base gets bubbly and hot, while the marshmallows puff up and toast to a gorgeous golden brown. It’s sweet, savory, creamy, and sticky all at once!

How to Make Sweet Potato Casserole

Quick Overview

Don’t let the stunning presentation fool you; making this sweet potato casserole is an absolute breeze. You’ll start by cooking your sweet potatoes until they are fall-apart tender. You can either boil them in a large pot or bake them in the oven—whichever method you prefer! Once they’re soft, you’ll mash them up with rich melted butter, a whole can of sweetened condensed milk, and our cozy blend of spices.

After you’ve achieved a silky smooth texture, you simply spread the mixture into a greased baking dish. The final, and arguably most fun, step is blanketing the top with marshmallows and baking it until everything is bubbly and the topping is beautifully toasted. It’s truly that simple!

Ingredients

You only need a handful of simple, affordable ingredients to bring this masterpiece to life. Here is what you’ll want to grab from the grocery store:

• Sweet Potatoes: You’ll need about 2.5 pounds. You can peel and dice them for boiling, or leave them whole if you plan to bake them.
• Butter: 8 tablespoons (one full stick) of unsalted butter, melted to mix effortlessly into the potatoes.
• Sweetened Condensed Milk: One 14-ounce can. This is the secret to that perfectly sweet, extra-creamy texture.
• Spices: 1 tablespoon of cinnamon and a 1/2 teaspoon of nutmeg. If you prefer, a few dashes of pumpkin pie spice works beautifully too!
• Salt: Just a 1/2 teaspoon to cut through the sweetness and enhance the flavors.
• Marshmallows: One 16-ounce bag. We love using the big, fluffy ones, but mini marshmallows work just as well!

Step-by-Step Instructions

Step 1: Preheat & Prep Your Pan

Start by preheating your oven to 350 degrees Fahrenheit. Grab a 9×13 glass casserole dish and give it a good coating of non-stick cooking spray so nothing sticks to the edges. Set that aside for later.

Step 2: Cook the Sweet Potatoes

If you’re boiling: Place your peeled and diced sweet potatoes into a large stock pot and cover them completely with water. Put the lid on, bring the water to a boil, and let them cook for about 15 minutes until they are fork-tender. Drain the water completely and put the potatoes back into the warm pot. If you prefer baking, just roast them whole until soft, let them cool slightly, and scoop the flesh right out of the skins!

Step 3: Mash and Season

To your cooked sweet potatoes, add the melted butter, the entire can of sweetened condensed milk, the cinnamon, nutmeg, and salt. Grab your potato masher (a large fork or a potato ricer works too) and mash away until the mixture is nice and smooth. Make sure all those wonderful spices are evenly distributed.

Step 4: Assemble the Casserole

Carefully transfer your creamy sweet potato mixture into the prepared 9×13 baking dish. Use a spatula or the back of a spoon to smooth out the top into a nice, even layer.

Step 5: Add Marshmallows and Bake

Line the entire top of the casserole with your marshmallows, packing them in so there are no empty gaps. Pop the dish into your preheated oven and bake for about 15 to 20 minutes. Keep a close eye on it—you want the marshmallows to puff up and turn a gorgeous, light golden brown. Serve it warm and watch it disappear!

What to Serve It With

Because this sweet potato casserole is such a classic, it pairs beautifully with almost any traditional holiday main course. We absolutely love serving it alongside a juicy Thanksgiving turkey—the savory gravy and the sweet potatoes are a match made in heaven. If you’re hosting Christmas or Easter, it is phenomenal next to a slow cooker ham or a beautifully baked ham with a sticky orange glaze.

Don’t forget the other side dishes! This casserole sits perfectly on a plate next to savory homemade sausage stuffing, creamy mashed potatoes, and a crispy, savory green bean casserole. The contrast of flavors is exactly what makes holiday dinners so special.

Top Tips for Perfecting Your Sweet Potato Casserole

You might think making the best sweet potato casserole your family has ever eaten is going to be stressful, but I promise it’s not! Over the years, I’ve learned a few tricks to ensure it turns out perfectly every single time.

• Watch the Oven Closely: Marshmallows can go from perfectly toasted to completely burnt in the blink of an eye. Keep a close watch during those last few minutes of baking. If the worst happens and they do burn, don’t panic! Just scrape off the charred layer completely, add fresh marshmallows, and try again.
• Try an Egg for a Lighter Texture: If you prefer your sweet potato base to be a little more airy and souffle-like, simply whip up one egg and fold it into the mashed sweet potato mixture before baking. It creates a wonderfully fluffy bite!
• Baked vs. Boiled: While both methods work great, baking your sweet potatoes whole tends to yield a slightly sweeter, more moist base since boiling can sometimes water them down. Plus, baking means you don’t have to peel raw potatoes!
• In a Pinch, Use Canned: If you absolutely cannot find fresh sweet potatoes, you can use drained, canned sweet potatoes. Just keep in mind that they are usually packed in syrup and will be much sweeter. Add your sweetened condensed milk slowly and taste as you go so it doesn’t become overly sugary.
• No Condensed Milk? No Problem: If you find yourself without sweetened condensed milk, you can substitute it with dark or light brown sugar (or even maple syrup) mixed with a hearty splash of heavy cream or half-and-half.

Storing and Reheating Tips

While this sweet potato casserole is definitely at its absolute best when served fresh out of the oven, the leftovers are still incredibly delicious and perfect for next-day snacking.

To Store: You can keep any leftovers in the refrigerator for up to 5 days. Just wrap your casserole dish tightly with plastic wrap to keep the air out. If you only have a little bit left, transferring it to an airtight container saves space in the fridge.

To Reheat: When you warm this up again, the marshmallows will likely melt down and evaporate a bit. It won’t look quite as fluffy and picture-perfect as day one, but the flavor will still be amazing. For the best results, replace the plastic wrap with aluminum foil and warm the casserole in a 350-degree oven until heated through. If you’re just heating a single serving, popping it in the microwave for a minute or two works perfectly fine!

Frequently Asked Questions

Final Thoughts

There is something incredibly special about recipes that get passed down and shared around a crowded holiday table year after year. This sweet potato casserole with marshmallows isn’t just food; it’s a bowl full of memories, comfort, and tradition. The creamy, spiced sweet potatoes paired with that sticky, toasted marshmallow topping is a combination that never, ever gets old.

I hope this dish brings as much joy to your family dinners as it has to mine. Don’t be surprised if your guests start requesting that you make this for every single gathering from now on! Happy cooking, and enjoy every single gooey 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)
• 14 oz sweetened condensed milk 1 can
• 1 tablespoon cinnamon
• 0.5 teaspoon nutmeg
• 0.5 teaspoon salt
• 16 oz large marshmallows 1 bag (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.