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Sweet Potato Casserole with Pecan Crumble & Marshmallow Topping: The Ultimate Holiday Side

More Than Just a Side Dish: It’s a Hug on a Plate

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Hello, my friend! Can you smell it? That unmistakable aroma of cinnamon and brown sugar wafting through a warm, bustling kitchen? It’s the scent of celebration, of gathered loved ones, and for so many of us, it’s the smell of a glorious Sweet Potato Casserole making its grand entrance. If you’ve ever thought this beloved dish was just a simple side, I’m here to let you in on a little secret: it’s the undisputed star of the holiday table.

Today, I’m sharing my ultimate, crowd-pleasing, double-batch version of this classic. We’re talking velvety, spiced sweet potatoes, a buttery, nutty pecan crumble that gives you the most satisfying crunch, and a fluffy, golden blanket of toasted marshmallows. This isn’t just a recipe; it’s a flavor and texture experience. It’s the dish that disappears first, the one people quietly sneak a second spoonful of, and the one that sparks the happiest of food memories.

I know holiday cooking can feel a little overwhelming, but I promise you, this recipe is your joyful escape. It’s straightforward, forgiving, and crafted with so much love. Whether you’re hosting a full house or contributing to a potluck, this casserole is your ticket to becoming a holiday legend. So, take a deep breath, put on your favorite apron, and let’s create some magic together. This is the Sweet Potato Casserole of your dreams, and I can’t wait for you to make it.

The Casserole That Started It All

My love affair with this dish began not in a fancy kitchen, but at my Grandma Eleanor’s Formica-topped table. Every Thanksgiving, she’d let me be her official “Marshmallow Placer.” While she handled the savory dishes with serious focus, she’d hand me the bag of mini marshmallows and give me one joyous task: create a perfect, single layer over the hot, pecan-dotted filling. I took this job with the gravity of a master architect, carefully placing each fluffy puff until not a single square inch of orange filling was visible.

The magic happened when we opened the oven for the final bake. We’d jostle for space at the oven light, watching as those pristine white pillows slowly puffed, turned a beautiful golden-brown, and fused together into one glorious, gooey masterpiece. That first bite—the crackle of the toasted marshmallow giving way to the crunchy pecans and the warm, spiced sweet potato beneath—was pure, unadulterated joy. It taught me that the best recipes aren’t just about taste; they’re about the stories we create while making them. This casserole is my edible hug from Grandma Eleanor, and now, I’m so thrilled to share it with you.

Gathering Your Magical Ingredients

This is a double-batch recipe, perfect for a big crowd or for guaranteeing you have glorious leftovers (which, in my opinion, are even better the next day!). Don’t let the quantity scare you—the process is wonderfully simple. Here’s everything you’ll need, with a few of my chef-y insights to help you along the way.

For the Sweet Potato Filling:

• 8 large sweet potatoes (about 18 cups), peeled and chopped – This is our foundation! Look for potatoes that are firm and heavy for their size. Pro tip: Cubing them before boiling makes them cook faster and more evenly than boiling them whole.
• 1 cup unsalted butter, melted – This adds incredible richness and a silky mouthfeel. Using unsalted lets you control the seasoning perfectly.
• 2 cups brown sugar – This is our primary sweetener, and it brings that deep, almost caramel-like molasses flavor that white sugar just can’t match.
• 1 teaspoon salt – Never skip the salt! It’s the secret weapon that makes all the sweet and spicy flavors pop. It balances the dish beautifully.
• 1 teaspoon ground cinnamon & ½ teaspoon ground nutmeg – The classic warm spice duo. They make the kitchen smell like the holidays and add that essential cozy depth.
• 2 teaspoons vanilla extract – A splash of vanilla adds a beautiful, floral aroma that rounds out all the other flavors. It’s a simple upgrade that makes a huge difference.

Flavor Twist Add-ins (Pick one or mix and match!):

• ½ teaspoon ground ginger: Adds a little peppery warmth that pairs so well with the sweet potato.
• Zest of 1 orange: My personal favorite! The bright, citrusy notes cut through the richness and make the whole dish taste fresher.
• ¼ cup maple syrup: Swap out ¼ cup of the brown sugar for pure maple syrup for an extra layer of autumnal flavor.

For the Pecan Crumble Topping:

• 8 tablespoons unsalted butter, melted – This binds our crumble together and helps it get deliciously crispy in the oven.
• ⅔ cup brown sugar – Creates a delicious caramelization with the butter and toasts the pecans to perfection.
• 4 tablespoons all-purpose flour – This is the structure-builder for our crumble, giving it that delightful, clumpy texture.
• 1 teaspoon salt – A pinch of salt in the topping balances its sweetness and enhances the nutty flavor of the pecans.
• 2½ cups finely chopped pecans – Toasting them beforehand is a game-changer! Just pop them in a dry skillet for a few minutes until fragrant. It unlocks their oils and makes them incredibly flavorful.

Optional Savory Upgrade:

• ¼ teaspoon cayenne or smoked paprika: Don’t knock it ’til you’ve tried it! A tiny hint of heat or smoke creates a fascinating and delicious contrast to the sweetness.

For the Marshmallow Layer:

• 20 oz mini marshmallows – The grand finale! Minis are ideal because they create an even, seamless layer that toasts beautifully. If you only have large marshmallows, just give them a rough chop before scattering them over the top.

Let’s Build Your Masterpiece, Step-by-Step

Ready to create some kitchen magic? Follow these steps, and you’ll have a flawless casserole that’s as fun to make as it is to eat. I’ve tucked my favorite little chef hacks into each step to make you feel like a pro.

1. Preheat and Prep: Fire up your oven to 350°F (175°C). This is our sweet spot—hot enough to cook the casserole and toast the toppings without burning. While it heats, grab your largest pot and fill it with water. Add a generous pinch of salt—this seasons the potatoes from the inside out as they boil.
2. Cook the Sweet Potatoes: Add your peeled and cubed sweet potatoes to the pot. Bring it to a rolling boil and let them cook for about 15-20 minutes, or until they are completely fork-tender. You should be able to pierce a cube with no resistance. Chef’s Hack: Don’t overcook them to mush, or they’ll become waterlogged. We want them tender but not swimming!
3. Drain and Mash: Carefully drain the potatoes in a colander and let them steam dry for a minute. This gets rid of excess moisture, which is the enemy of a fluffy casserole. Transfer them back to the warm pot (off the heat) or to a large mixing bowl. Now, mash them until they’re perfectly smooth! You can use a potato masher, a ricer (for the silkiest texture), or even the paddle attachment on a stand mixer. No lumps allowed here!
4. Create the Filling: Pour in the 1 cup of melted butter, the 2 cups of brown sugar, 1 tsp salt, cinnamon, nutmeg, and vanilla. If you’re using any of the flavor twist add-ins (I highly recommend the orange zest!), add them now. Mix everything together until it’s beautifully combined and silky. Chef’s Hack: Taste it! This is your moment to adjust. Want a touch more cinnamon? Go for it! This is your creation.
5. First Bake: Spread this glorious sweet potato mixture evenly into your 9×13-inch baking dish (or divide it between two smaller ones). Now, let’s make the crumble! In a medium bowl, mix the 8 tablespoons of melted butter, ⅔ cup brown sugar, flour, salt, and chopped pecans. Use a fork to combine it until it looks like a delicious, clumpy, buttery sand. Sprinkle this evenly over the entire surface of the sweet potatoes. Pop the dish, uncovered, into your preheated oven and bake for 20-25 minutes. This step sets the base and toasts the pecan crumble.
6. The Marshmallow Moment: Carefully pull the casserole out of the oven—it should be bubbly around the edges and smell amazing. Now, quickly and evenly scatter the entire bag of mini marshmallows over the hot pecan topping. Chef’s Hack: For maximum golden-toasting coverage, I like to do one layer, let it sit for 30 seconds to just start melting, then add a second light layer in any gaps.
7. Final Toast: Return the casserole to the oven for the final 10-15 minutes. Watch it closely! You’re looking for the marshmallows to be puffed, soft, and beautifully golden brown. They can go from perfect to overdone quickly, so don’t wander off. Once they’re a gorgeous toasted color, take it out and let it rest for at least 10-15 minutes before serving. It will be molten-lava hot, and this rest time allows everything to set just enough for perfect serving.

Serving Up the Sunshine

Presenting this beauty is part of the fun! I love serving it straight from the baking dish at the table—it’s a real showstopper. Use a large spoon or a sturdy spatula to scoop out generous portions, making sure you get every layer in each serving: that gooey marshmallow top, the crunchy pecan middle, and the creamy sweet potato base. It pairs magnificently with all your holiday classics, but it’s particularly dreamy next to savory roast turkey, a glossy glazed ham, or my favorite herby green bean casserole. The contrast is everything!

Make It Your Own: Delicious Twists & Swaps

This recipe is a wonderful canvas for your creativity! Here are a few of my favorite ways to mix it up:

• Nut-Free Bliss: Swap the pecans for an equal amount of old-fashioned rolled oats for a fantastic, crunchy streusel topping.
• Bourbon Caramel Kick: Stir 2-3 tablespoons of bourbon into the sweet potato filling along with the vanilla for a sophisticated, grown-up twist.
• Maple Pecan Dream: Replace the brown sugar in the filling with pure maple syrup and use maple sugar in the pecan crumble for an intensely maple-flavored experience.
• Marshmallow-Free Zone: If you’re not a marshmallow person (no judgment!), simply double the pecan crumble recipe and bake it for the full 30-35 minutes. It’s just as iconic!
• Make-Ahead Magic: Assemble the casserole completely with the pecan topping (but not the marshmallows), cover tightly, and refrigerate for up to 2 days. When ready to bake, add 5-10 minutes to the initial bake time, then add marshmallows and finish as directed.

Anna’s Kitchen Notes & Stories

This recipe has been on quite a journey with me! The first time I made it for my now-husband’s family, I was so nervous that I accidentally used salted butter and didn’t adjust the salt. Let’s just say it was… an assertive casserole. We still laugh about it! I learned my lesson, and now I’m a staunch advocate for unsalted butter. Over the years, I’ve tweaked and perfected it—adding the orange zest was a revelation one year when I had a bowl of citrus on the counter, and the cayenne option came from a daring dinner party experiment that was a huge hit.

The biggest evolution, though, was turning it into this trusty double-batch. It came from the year I hosted 20 people and my single dish was gone in what felt like 60 seconds. The look of disappointment on my cousin’s face when he went for seconds and found an empty dish? Heartbreaking! Now, I always make the big batch. It freezes beautifully (without marshmallows), and having a spare in the freezer for a cozy winter night feels like a gift from Past Anna to Future Anna. You’ll thank yourself, I promise.

Your Questions, Answered!

I’ve gotten so many wonderful questions about this recipe over the years. Here are the ones that pop up most often, to help you troubleshoot like a pro.

Can I use canned sweet potatoes?

You absolutely can for a shortcut! Drain two 40-oz cans of sweet potatoes (in water, not syrup) very well. You might even want to pat them dry with a paper towel to remove excess moisture. Follow the recipe from the mashing stage. The flavor and texture will be best with fresh, but canned is a perfectly good time-saver!

My casserole is too runny. What happened?

This is almost always a moisture issue. The two main culprits are: 1) The sweet potatoes weren’t drained and dried enough after boiling, or 2) They were overcooked and absorbed too much water. To fix it for next time, after draining, return the potatoes to the warm, empty pot and stir them over low heat for a minute to evaporate any extra liquid. For a rescue mission on a runny batch, just bake it for an extra 10-15 minutes (before adding marshmallows) to help it firm up.

Can I make this ahead of time?

Yes, and it’s a lifesaver! Prepare the sweet potato filling and spread it in the dish. Make the pecan crumble and store it in a separate zip-top bag in the fridge. The day you want to serve it, let the dish come to room temperature for 30 minutes, sprinkle on the cold crumble, and bake as directed, adding a few extra minutes to the initial bake time since everything is starting out cold.

My marshmallows are burning before the casserole is hot! Help!

This is a common oven quirk! If you notice the marshmallows browning too quickly, simply lay a loose piece of aluminum foil over the top for the remainder of the baking time. This will shield them from direct heat and prevent burning while the inside continues to heat through. You can also try moving the dish to a lower rack in your oven.

A Quick Nutritional Glance

Please note: This is an estimated breakdown per serving (based on 16 servings) and can vary based on specific ingredients used.

• Calories: ~330
• Fat: 18g
• Carbohydrates: 35g
• Protein: 3 

Final Thoughts

There’s just something magical about a dish that can silence a crowded room — and this Sweet Potato Casserole does exactly that. With its silky, spiced base, buttery pecan crumble, and golden, toasted marshmallow crown, it’s the perfect balance of cozy and celebratory. It’s more than just a side dish; it’s that nostalgic, heartwarming bite that instantly transports you back to the happiest holiday tables.

What I love most is how it carries stories — of family kitchens, shared laughter, and those small, beautiful traditions that make the holidays feel like home. Whether you stick to the classic version or add your own twist, this casserole is pure comfort on a spoon.

So go ahead and make the double batch. Your future self (and your guests) will thank you — because when the plates are cleared and the leftovers are gone, this is the dish everyone will still be talking about. 🧡🍠✨