Sweet Potato Marshmallow Casserole

This irresistible sweet potato casserole combines the creamy comfort of perfectly spiced mashed sweet potatoes with a golden topping of mini marshmallows and crunchy pecans that creates the ultimate holiday side dish. Every spoonful delivers layers of flavor from warm cinnamon and nutmeg, rich brown sugar, and that perfect contrast between the fluffy marshmallows and buttery pecan crunch. It's the kind of dish that brings families together around the table, with everyone fighting for that last corner piece where the marshmallows get extra golden and crispy.

I'll never forget the first time I served this at Thanksgiving when my skeptical father-in-law, who claimed to hate sweet potatoes, went back for thirds and quietly asked for the recipe. That's when I knew this casserole was something special - it has this magical ability to convert even the most stubborn sweet potato doubters into believers. Now it's become such a requested dish that I actually make two casseroles for every holiday gathering because one is never enough, and I've learned that people get genuinely disappointed if I show up without it.

Ingredients

• Sweet potatoes (3.5 lbs, about 4-5 large) - Choose firm, unblemished potatoes with smooth skin for the best flavor and texture when mashed
• Unsalted butter (12 tablespoons total) - Divided between the sweet potato base and the crumbly topping for rich, luxurious flavor throughout
• Light brown sugar (1½ cups total) - Enhances the natural sweetness of the potatoes while adding those lovely caramel notes
• Large eggs (2, lightly beaten) - Help bind the sweet potato mixture and create that perfect creamy, custard-like texture
• Ground cinnamon (1½ teaspoons total) - The essential warm spice that makes this taste like the holidays in every bite
• Ground nutmeg (¼ teaspoon) - Adds depth and complexity that elevates the flavor beyond ordinary sweet potato dishes
• Salt (1¼ teaspoons total) - Balances the sweetness and enhances all the other flavors beautifully
• All-purpose flour (½ cup) - Creates the perfect crumbly topping texture that holds everything together
• Chopped pecans (1 cup) - Provides essential crunch and nutty richness that complements the sweet elements perfectly
• Mini marshmallows (2 cups) - The crowning glory that transforms this from ordinary to extraordinary with their golden, gooey perfection

Instructions

Prepare your oven and casserole dish.

Preheat your oven to 350°F and generously grease a 9x11 inch casserole dish with butter or cooking spray. This prevents sticking and ensures easy serving later, especially important with the sticky marshmallow topping.

Cook the sweet potatoes to perfect tenderness.

Peel the sweet potatoes and cut them into large, uniform chunks for even cooking. Place them in a large pot of salted water, bring to a boil, then reduce heat and simmer for 22-25 minutes until completely fork-tender. You want them soft enough to mash easily without any lumps.

Drain and cool the potatoes properly.

Drain the cooked sweet potatoes thoroughly in a colander and let them cool for about 15 minutes. This cooling time allows excess moisture to evaporate, which prevents your casserole from becoming watery and helps achieve that perfect creamy texture.

Create the signature crumbly topping.

In a medium mixing bowl, combine 1 cup brown sugar, flour, chopped pecans, 1 teaspoon cinnamon, and ¼ teaspoon salt. Add 6 tablespoons of melted butter and stir until the mixture resembles coarse crumbs that hold together when squeezed.

Add marshmallows to complete the topping.

Gently fold the mini marshmallows into your crumbly mixture, being careful not to break them up. This creates that perfect combination of textures that makes each bite so interesting and delicious.

Mash the sweet potatoes to silky smoothness.

In a large mixing bowl, mash the cooled sweet potatoes until mostly smooth - a few small lumps are fine and actually add nice texture. Add the remaining 6 tablespoons of softened butter and continue mashing until well incorporated.

Season the sweet potato base perfectly.

Add the remaining ½ cup brown sugar, 1 teaspoon salt, ½ teaspoon cinnamon, nutmeg, and beaten eggs to the mashed sweet potatoes. Mix everything together until completely smooth and well combined, tasting and adjusting seasonings if needed.

Assemble the casserole for baking.

Spread the seasoned sweet potato mixture evenly in your prepared casserole dish, smoothing the top with a spatula. Distribute the marshmallow and pecan topping evenly over the surface, making sure to cover all the way to the edges.

Bake to golden perfection.

Bake uncovered for 35-40 minutes, until the marshmallows are beautifully golden brown and the edges are bubbling slightly. If the marshmallows brown too quickly, tent loosely with foil sprayed with cooking spray to prevent sticking.

Cool before serving for best results.

Let the casserole rest for 10 minutes before serving to allow it to set up properly. This makes it much easier to serve neat portions and prevents the topping from sliding off when you scoop it.

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Achieving the Perfect Sweet Potato Texture

The secret to an amazing sweet potato casserole lies in properly preparing the base, and that starts with choosing the right potatoes and cooking them correctly. Look for sweet potatoes that feel heavy for their size and have smooth, unblemished skin. The cooking method matters too - boiling them in chunks rather than baking whole potatoes creates a more consistent texture and prevents any dry or stringy areas.

Don't skip the cooling step after draining the potatoes. This time allows excess moisture to evaporate, which is crucial for preventing a watery casserole. When mashing, aim for mostly smooth with just a few small lumps for texture - completely smooth can sometimes feel gluey, while too many lumps make the casserole feel unfinished.

The Magic of the Marshmallow Topping

The marshmallow and pecan topping is what transforms this from a simple sweet potato dish into something truly special. The mini marshmallows are key here - regular-sized marshmallows don't distribute as evenly and can create hot spots that burn before the rest of the topping is golden. As they bake, the marshmallows develop a slightly crispy exterior while staying gooey inside, creating that perfect textural contrast.

The pecans provide essential crunch and nutty richness that balances the sweetness of the marshmallows and sweet potatoes. If you can't find pecans or prefer a different nut, walnuts work well too, though they have a slightly more robust flavor. Toast the nuts lightly before chopping for even more flavor depth.

Make-Ahead Strategies for Stress-Free Holidays

This casserole is a dream for holiday meal planning because it actually improves when made ahead. You can assemble the entire dish up to 24 hours before baking - just cover tightly with plastic wrap and refrigerate. When ready to bake, let it come to room temperature for about 30 minutes, then bake as directed, adding an extra 5-10 minutes if needed.

You can also prepare just the sweet potato base up to two days ahead and refrigerate it separately from the topping. When ready to serve, spread the sweet potato mixture in your casserole dish, add the topping, and bake. This method ensures the marshmallows and pecans stay crispy rather than getting soggy from sitting on the moist sweet potato base.

Storage and Reheating Tips

Leftover sweet potato casserole keeps beautifully in the refrigerator for up to five days when stored in an airtight container. The flavors actually meld and improve after a day or two, making leftovers something to look forward to rather than just tolerate. For the best reheating results, use the oven rather than the microwave to maintain the texture of the topping.

To reheat, preheat your oven to 350°F and bake covered for 20-25 minutes until heated through. For the last five minutes, remove the cover and add a handful of fresh mini marshmallows on top to recreate that golden, crispy surface that makes this casserole so appealing. The microwave works in a pinch but will soften the topping.

Customizing for Different Dietary Needs

This recipe is easily adaptable for various dietary restrictions without sacrificing flavor or appeal. For gluten-free guests, simply substitute the all-purpose flour in the topping with your favorite gluten-free flour blend - the texture will be virtually identical. For vegetarian diners, swap regular marshmallows for gelatin-free versions, which are becoming increasingly available in regular grocery stores.

If you want to reduce the sweetness slightly, you can cut the brown sugar in the sweet potato base by half without significantly affecting the texture. Adding a tablespoon of orange zest or a splash of bourbon to the sweet potato mixture creates more complex, adult-friendly flavors that complement the basic recipe beautifully.

I've made this casserole for countless holiday gatherings over the years, and it never fails to be one of the first dishes to disappear from the table. There's something so comforting about that combination of creamy sweet potatoes and golden marshmallow topping that speaks to everyone's inner child while still feeling sophisticated enough for adult dinner parties. My kids always volunteer to help make it because they love being in charge of sprinkling the marshmallows on top, and I love that it's become part of our family's holiday traditions.

This recipe represents everything I love about holiday cooking - it brings people together, creates lasting memories, and proves that sometimes the most beloved dishes are the ones that combine simple ingredients in magical ways. Every time I make this casserole, I'm reminded that food is about so much more than just nutrition - it's about comfort, tradition, and the joy of sharing something delicious with the people we care about most.

Frequently Asked Questions

→ Can I make this casserole ahead of time?

Yes, you can assemble it the day before and bake when ready. Just add 5-10 extra minutes if baking from cold.

→ What if I don't have mini marshmallows?

You can cut regular marshmallows into smaller pieces or skip them entirely for just the pecan topping.

→ How do I know when the sweet potatoes are done cooking?

They should be fork tender after 22-25 minutes of boiling. A fork should go through easily with no resistance.

→ Can I use canned sweet potatoes instead?

Fresh sweet potatoes work best, but you can use about 3 cups of drained canned sweet potatoes if needed.

→ Why are my marshmallows burning?

Cover loosely with foil if they brown too quickly. The foil should be sprayed with cooking spray so it doesn't stick.

→ How long does this casserole keep?

It will stay fresh in the fridge for 3-4 days. Reheat individual portions in the microwave or oven.