Classic Sweet Potato Casserole with Toasted Marshmallows

An icon representing a clock 1 h 10 min | easy
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Introduction

This classic sweet potato casserole is rich, buttery, and perfectly spiced, with a silky smooth filling that feels so cozy.

A blanket of toasted mini marshmallows on top adds that nostalgic, golden-brown crunch and gooey sweetness everyone loves.

It’s a must-have side dish for Thanksgiving, Christmas, or any holiday table, and it pairs beautifully with roasted turkey or ham.

Ingredients  (8 servings)

Ingredients for the Sweet Potato Filling:

Ingredients for the Topping:

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Slice of sweet potato casserole on a white plate, topped with mini marshmallows toasted golden on top; baking dish with more casserole blurred in the background.

How to Make Classic Sweet Potato Casserole with Toasted Marshmallows

  1. Prep the pan and oven

    Butter a 9x13-inch baking dish and preheat your oven to 350°F.

  2. Cook the sweet potatoes

    Place the sweet potato chunks in a large pot and cover them with cold water by about an inch.

    Add a pinch of salt, then bring the pot to a boil over medium-high heat.

    Reduce the heat and simmer until the potatoes are very tender, about 15 to 20 minutes.

    Drain the potatoes well and return them to the warm pot to let steam escape.

  3. Mash the potatoes

    Mash the sweet potatoes until very smooth, using a potato masher or hand mixer on low speed.

  4. Mix the sweet potato filling

    Stir in the melted butter, brown sugar, heavy cream, vanilla, cinnamon, nutmeg, and salt until fully blended.

    Let the mixture cool for several minutes until it feels warm but not hot to your touch.

    Whisk the eggs in a small bowl, then quickly stir them into the sweet potato mixture.

  5. Bake the filling

    Spread the sweet potato mixture evenly in the prepared baking dish and smooth the top with a spatula.

    Bake uncovered for 20 to 25 minutes, until the edges look slightly puffed and the center feels set.

  6. Top with marshmallows and toast

    Carefully remove the dish from the oven and scatter the mini marshmallows evenly over the hot surface.

    Return the casserole to the oven and bake for 8 to 10 minutes, until the marshmallows are puffed and golden.

    For deeper color, broil for 1 to 2 minutes, watching constantly so the marshmallows do not burn.

  7. Rest and serve

    Let the casserole rest for about 10 minutes so it sets slightly and is easier to scoop.

Overhead view of sweet potato casserole: a mound of bright orange mashed sweet potatoes on a white plate topped with lightly toasted mini marshmallows, with part of a baking dish in the top-right corner.

Substitutions

Heavy cream -> whole milk
Use the same amount of whole milk to lighten the casserole while keeping it creamy and spoonable.
Butter -> refined coconut oil
Swap melted butter for refined coconut oil for a dairy-free option with a subtle, almost caramel sweetness.
Mini marshmallows -> pecan streusel topping
Top the casserole with chopped pecans, brown sugar, and melted butter for a crunchy, less-sweet finish with nutty richness.
Baked sweet potato casserole in a white rectangular dish, topped with puffed mini marshmallows toasted golden brown on top, on a light countertop with a white tile backsplash.

Tips

Pick the right sweet potatoes
Choose orange-fleshed varieties like garnet or jewel, which mash silky and naturally sweet without needing extra sugar.
Dry out the potatoes
After draining, let the potatoes sit in the warm pot so excess moisture evaporates and the casserole will not turn soupy.
Temper the eggs
Always let the sweet potato mixture cool slightly before adding eggs, so they mix in smoothly instead of scrambling.
Make it ahead
Assemble the filling in the dish, cover, and refrigerate up to two days, then bake and add marshmallows right before serving.
Control the sweetness
Use fewer marshmallows or reduce the brown sugar slightly if you prefer a more gently sweet, less dessert-like casserole.
Get even browning on the topping
Rotate the dish halfway through toasting the marshmallows, especially under the broiler, so every corner browns evenly.

Nutrition Facts *

Energy 304 kcal
Protein 3 g
Total Fat 15 g
Carbohydrates 39 g
Dietary Fiber 3 g

* Approximate, per serving.
Data source: USDA FoodData Central.

Serving of sweet potato casserole on a white plate, topped with mini marshmallows toasted golden on top; the remaining casserole sits in a white baking dish in the background.

FAQ

Why is my sweet potato casserole watery or loose?
Too much moisture usually means the potatoes were undercooked, not drained well, or the filling did not bake long enough. Next time, simmer until very tender, steam off water in the pot, and extend baking until the center firms.
Can I use canned sweet potatoes instead of fresh?
Yes, canned sweet potatoes work, but drain them very well and skip any packed syrup. Reduce the brown sugar slightly, since canned sweet potatoes are usually sweeter than fresh and can make the casserole cloying.
How far in advance can I make this casserole?
You can assemble the unbaked filling up to two days ahead and refrigerate it tightly covered. Let it sit at room temperature for 20 to 30 minutes, then bake and add marshmallows as directed.
How can I make this recipe less sweet?
Use 6 to 8 tablespoons of brown sugar instead of the full half cup in the filling. You can also cover only part of the casserole with marshmallows, leaving one side plain or topped with nuts.
How do I keep the marshmallows from burning?
Keep the dish on the middle rack and watch constantly during the last few minutes of toasting or broiling. If the tops brown too fast, loosely tent foil over the dish or move it to a lower rack.

Serving Suggestions

This cozy casserole practically begs to sit beside roasted turkey, glazed ham, or a simple roasted chicken dinner.

Try sprinkling chopped toasted pecans over just half the pan to offer both a classic marshmallow side and a crunchy version.

For a warm, bakery-style aroma, add a pinch of ground cloves or cardamom to the filling before baking.

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