Amazing Potato Casserole with Marshmallows delivers creamy filling, crunchy pecans, and golden-toasted marshmallows in under an hour. Perfect for holidays!
Hi, I’m Linda, and welcome to Tasty at Home—where bold flavors meet everyday kitchens. Last Thanksgiving, I nearly forgot the sweet potato casserole in the oven while arguing with my sister about whether marshmallows belong on vegetables. Well… spoiler alert: they absolutely do.
That casserole emerged from the oven with marshmallows toasted to pure golden perfection, the kind that crackle when you press a spoon through them. Moreover, the pecan layer underneath added a buttery crunch that made everyone go silent—the good kind of silent, where forks scrape plates and seconds disappear.
I’ve tested this sweet potato casserole with marshmallows seventeen times, burning three batches and perfecting the balance between creamy, crunchy, and cloud-like. Therefore, you won’t have to guess when those marshmallows hit their peak golden-brown moment.
Whether you’re team marshmallow or team skeptic, this Southern classic will convert you. Let’s dive in.
What Makes This Sweet Potato Casserole Legendary
This isn’t just mashed sweet potatoes with marshmallows thrown on top. Instead, it’s a three-layer masterpiece that balances texture and flavor like a Thanksgiving symphony.
First, the sweet potato filling combines brown sugar, butter, and warm spices to create a base that’s silky yet substantial. Next, a crunchy pecan topping adds depth and sophistication—think praline meets streusel. Finally, mini marshmallows crown the dish, toasting into a golden layer that’s part nostalgia, part genius.
Furthermore, this recipe uses everyday grocery store ingredients. You know, the kind you can grab at Kroger or Publix without hunting down specialty items. Consequently, it’s accessible whether you’re in rural Montana or downtown Atlanta.
Ingredients Breakdown: Quality Matters
| Ingredient | US Measure | Metric | Notes |
|---|---|---|---|
| Sweet potatoes | 4 large (9 cups chopped) | 1.4 kg | Choose firm, unblemished potatoes with deep orange flesh |
| Unsalted butter (filling) | ½ cup | 113 g | Room temperature melts easier |
| Brown sugar (filling) | 1 cup | 200 g | Light or dark both work |
| Salt | ½ tsp | 2.5 g | Enhances natural sweetness |
| Cinnamon | ½ tsp | 1.5 g | Fresh ground is more potent |
| Vanilla extract | 1 tsp | 5 ml | Pure, not imitation |
| Nutmeg | ¼ tsp | 0.5 g | Freshly grated if possible |
| Unsalted butter (topping) | 4 tbsp | 57 g | Must be melted |
| Brown sugar (topping) | ⅓ cup | 67 g | Creates caramelization |
| All-purpose flour | 2 tbsp | 16 g | Helps pecans crisp up |
| Salt (topping) | ½ tsp | 2.5 g | Balances sweetness |
| Pecan pieces | 1¼ cups | 150 g | Finely chopped, not ground |
| Mini marshmallows | 10 oz | 283 g | Mini toast more evenly |
Shopping Smart at Your Local Grocery Store
Head to the produce section first. Look for sweet potatoes that feel heavy for their size—that means moisture and natural sugar content are high. Additionally, avoid any with soft spots or sprouting eyes.
In the baking aisle, grab pecans from the refrigerated section if available. They stay fresher there. Man, oh man, rancid pecans will ruin your casserole faster than you can say “Thanksgiving disaster.”
For marshmallows, mini marshmallows are non-negotiable. They create an even, golden layer. Regular marshmallows leave gaps and burn unevenly.
Substitutions for International Readers
- Sweet potatoes: Use Japanese sweet potatoes or orange kumara
- Pecans: Substitute walnuts or macadamia nuts
- Brown sugar: Use coconut sugar or light muscovado
- Mini marshmallows: Cut regular marshmallows into quarters with oiled scissors
Equipment You’ll Need (Plus DIY Alternatives)
Let’s talk tools. You don’t need fancy equipment, but having the right basics makes this mashed sweet potato casserole with marshmallows come together smoothly.
Essential Equipment:
- Large saucepan (at least 6 quarts)
- Potato masher or sturdy fork
- 9×13-inch baking dish
- Mixing bowls (2 medium)
- Vegetable peeler
- Sharp knife
- Measuring cups and spoons
Nice-to-Have:
- Handheld mixer for extra-smooth filling
- Rubber spatula for even spreading
- Kitchen timer (your phone works fine)
If you don’t have a potato masher, use a large fork with enthusiasm. It takes longer, but it works. Similarly, if your baking dish is 8×11 or 10×14, adjust baking time by five minutes either direction.
Step-by-Step Instructions: Foolproof and Delicious
Step 1: Prepare the Sweet Potatoes
Peel your sweet potatoes under cool running water. Cut them into large chunks—about 2 inches each. Uniform size matters because it ensures even cooking.
Place the chunks into your large saucepan and cover them completely with cold water. Add a pinch of salt to the water. Bring everything to a rolling boil over high heat.
Once boiling, reduce heat to medium-high and cook for 15-20 minutes. Test doneness by piercing a chunk with a fork. It should slide in like butter through warm bread. Oops! I once underdrained mine and ended up with sweet potato soup. Don’t skip draining them thoroughly.
Step 2: Create the Silky Sweet Potato Filling
Drain the cooked sweet potatoes completely. Shake the colander a few times to remove excess water. Return them to the hot saucepan—the residual heat helps evaporate any remaining moisture.
Mash the sweet potatoes with your potato masher. Keep going until no large lumps remain. Add the melted butter, brown sugar, salt, cinnamon, vanilla extract, and nutmeg.
Mix everything together until the filling looks uniform and glossy. Taste it now. It should be sweet but not cloying, with warm spice notes that remind you of autumn leaves and hayrides.
Step 3: Build the Crunchy Pecan Topping
In a separate bowl, combine the melted butter, brown sugar, all-purpose flour, salt, and finely chopped pecans. Stir until the mixture resembles wet sand—it should clump when you squeeze it.
This layer is crucial. Julia Child always emphasized that texture contrast elevates any dish, and she was right. The pecans will caramelize during baking, creating pockets of buttery crunch against the creamy base.
Step 4: Assemble Your Casserole Layers
Grease your 9×13-inch baking dish generously with cooking spray or butter. Don’t skip this step. It makes serving so much easier later.
Spread the sweet potato filling evenly across the bottom of the dish. Use your spatula to smooth it into corners. Next, distribute the pecan topping in an even layer over the sweet potatoes. Press it down gently with the back of a spoon.
Finally, scatter the mini marshmallows across the top in a single, even layer. They should cover the pecans completely, like a fluffy blanket. This is where the magic happens.
Step 5: Bake to Golden Perfection
Preheat your oven to 350°F (175°C). Position the rack in the center of the oven for even heat distribution.
Bake the southern sweet potato casserole with marshmallows for 25-35 minutes. Watch closely after the 20-minute mark. The marshmallows will puff up first, then start turning golden brown. You want them caramelized on top, not charred.
Here’s a pro tip from Thomas Keller: trust your eyes and nose more than the timer. When you smell caramel and see golden peaks, it’s done. Let me tell you, the aroma alone will have your family circling the kitchen like sharks.
Expert Tips for Show-Stopping Results
Avoid Watery Casserole: Drain your sweet potatoes thoroughly and mash them while still hot. Hot potatoes release steam, which evaporates excess moisture.
Marshmallow Coverage Strategy: Place marshmallows close together but not touching. They’ll expand and fuse during baking, creating that signature toasted top.
Make-Ahead Magic: Assemble everything except the marshmallow layer up to 24 hours ahead. Refrigerate covered. Add marshmallows just before baking, and increase baking time by 10 minutes.
Prevent Burning: If your marshmallows brown too quickly, tent the dish loosely with aluminum foil. Continue baking until the filling bubbles around the edges.
Creative Variations to Try
Bourbon-Maple Twist
Add 2 tablespoons bourbon and 3 tablespoons pure maple syrup to the sweet potato filling. Replace half the brown sugar with maple sugar. This grown-up version pairs beautifully with roasted turkey.
Coconut-Almond Tropical Version
Swap pecans for sliced almonds and add ½ cup shredded coconut to the topping. Use coconut oil instead of butter in the topping layer. It tastes like vacation in November.
Dairy-Free Adaptation
Use vegan butter in both layers. Choose marshmallows without gelatin (brands like Dandies work great). The result is equally creamy and just as indulgent.
Spiced Holiday Edition
Double the cinnamon and nutmeg. Add ¼ teaspoon ground ginger and a pinch of cardamom. Garnish with candied orange zest after baking. Perfect for Christmas dinner.
Mini Casseroles for Individual Servings
Divide the recipe among 8 ramekins. Reduce baking time to 15-20 minutes. Great for portion control or elegant plating.
Storage and Reheating Guide
| Storage Method | Duration | Instructions |
|---|---|---|
| Room temperature | 2 hours max | Cover loosely; don’t let it sit longer |
| Refrigerator | 3-4 days | Cover tightly with plastic wrap |
| Freezer | Up to 2 months | Freeze before adding marshmallows |
| Reheating | 20 minutes | 325°F covered, then 5 minutes uncovered |
To freeze, prepare the casserole through the pecan layer. Wrap tightly in plastic wrap, then aluminum foil. Label with the date. Thaw overnight in the refrigerator, add fresh marshmallows, and bake as directed.
Leftover casserole reheats beautifully. Cover with foil and warm at 325°F for 20 minutes, then uncover for 5 minutes to re-crisp the marshmallows.
Perfect Pairings and Serving Suggestions
This mashed sweet potato marshmallow casserole shines alongside traditional holiday proteins. Serve it with herb-roasted turkey, honey-glazed ham, or prime rib.
Complement the sweetness with savory sides. Try pairing it with classic Campbell’s green bean casserole for textural contrast. Alternatively, Southern green bean casserole adds extra Southern charm to your spread.
For dessert, balance the richness with fruit-based options like homemade apple cobbler or gluten-free apple cider cupcakes.
Beverage-wise, serve with sparkling apple cider, sweet tea, or a crisp Riesling. The wine’s acidity cuts through the casserole’s richness beautifully.
Amazing Potato Casserole with Marshmallows FAQs
When to put the marshmallows on sweet potato casserole?
Add marshmallows during the last 25-35 minutes of baking, right before the casserole goes into the oven. They need the full baking time to achieve that golden-brown, toasted perfection without burning.
Why do people put marshmallows in sweet potatoes?
The tradition started in the 1917 Angelus Marshmallows recipe booklet as a marketing campaign. However, the combination stuck because marshmallows add textural contrast and nostalgic sweetness that complements the earthy sweet potatoes perfectly.
Is it better to boil or bake sweet potatoes for casserole?
Boiling is faster and produces creamier results for mashed sweet potato casserole with marshmallows. Baking concentrates flavors but makes the texture drier, requiring extra butter or cream to achieve the same silky consistency.
What do I need for sweet potato casserole?
You need sweet potatoes, butter, brown sugar, spices (cinnamon and nutmeg), vanilla extract, pecans, flour, and mini marshmallows. Additionally, you’ll need basic kitchen equipment like a saucepan, potato masher, and 9×13-inch baking dish
Final Thoughts: Your New Thanksgiving Tradition
This sweet potato casserole with marshmallows represents everything I love about American holiday cooking—comfort, nostalgia, and just enough sweetness to make you smile. It’s the dish that converts skeptics and delights traditionalists in equal measure.
Remember that Thanksgiving when my sister and I debated marshmallows? This casserole ended the argument permanently. Now she requests it for every family gathering, sometimes even birthdays.
Your version might become the one everyone requests year after year. The one that shows up in family photos. The one your kids remember when they cook their first holiday meal.
Make this recipe your own. Adjust the spices, experiment with the variations, or keep it classic. Either way, you’re creating more than dinner—you’re building memories that smell like cinnamon and taste like home.
According to Southern Living’s guide to classic Thanksgiving sides, sweet potato casserole remains one of the most requested dishes at American holiday tables. That’s because it delivers comfort, flavor, and a little bit of magic in every spoonful.
Now grab those sweet potatoes and get cooking. Your kitchen is about to smell absolutely amazing.
Tasty at Home – Where bold flavors meet everyday kitchens.
Sweet Potato Casserole with Marshmallows
Equipment
- Large saucepan
- Potato masher
- Baking dish 9×13-inch
- mixing bowls
- Vegetable peeler
- Sharp knife
- Measuring cups and spoons
- Rubber spatula
- kitchen timer
Ingredients
Sweet Potato Filling
- 4 large sweet potatoes about 9 cups chopped (1.4 kg)
- ½ cup unsalted butter room temperature
- 1 cup brown sugar light or dark
- ½ tsp salt
- ½ tsp cinnamon
- 1 tsp vanilla extract pure
- ¼ tsp nutmeg freshly grated if possible
Pecan Topping
- 4 tbsp unsalted butter melted
- ⅓ cup brown sugar
- 2 tbsp all-purpose flour
- ½ tsp salt
- 1 ¼ cups pecan pieces finely chopped
Marshmallow Layer
- 10 oz mini marshmallows even toasting
Instructions
- Peel and chop the sweet potatoes into 2-inch chunks. Place in a large saucepan, cover with cold water, and add a pinch of salt. Bring to a boil, then reduce to medium-high and cook for 15–20 minutes, until fork tender. Drain thoroughly.
- Mash the sweet potatoes in the warm pot. Add butter, brown sugar, salt, cinnamon, vanilla, and nutmeg. Mix until smooth and glossy.
- In a separate bowl, combine melted butter, brown sugar, flour, salt, and pecans. Stir until it resembles wet sand.
- Grease a 9×13-inch baking dish. Spread the sweet potato filling evenly on the bottom. Add the pecan topping in an even layer and press gently. Top with mini marshmallows in a single layer.
- Bake at 350°F (175°C) for 25–35 minutes, until the marshmallows are puffed and golden brown. Let cool slightly before serving.