Sweet Potato Casserole with Marshmallows (Pecan Option)

Every family has its Thanksgiving must-haves, and in my house the sweet potato casserole with marshmallows is non-negotiable. Roasted sweet potatoes are whipped with butter, brown sugar, cinnamon and a splash of vanilla, then baked under a blanket of golden, toasty marshmallows.

Because my family is split between marshmallow fans and pecan fans, I often top half the dish with a buttery pecan streusel, and I show you exactly how below. You will also find ingredient notes, roasting versus boiling, step-by-step directions, variations, common fixes and a make-ahead plan. The full printable recipe card with measurements and estimated nutrition is at the bottom of the post.

Why This Sweet Potato Casserole Works

A great sweet potato casserole should taste like sweet potatoes first and dessert second. This version keeps the added sugar moderate, and roasting the potatoes concentrates their natural sweetness so the filling tastes rich and deeply caramelized.

• Roasted, not watery. Roasting instead of boiling keeps extra water out of the filling, so it bakes up creamy and never soupy.
• Light and fluffy. Two eggs give the filling a soft, almost souffle-like texture that holds its shape on the plate.
• Warm spices. Cinnamon, nutmeg and a pinch of ginger complement the sweet potatoes without overpowering them.
• Two toppings, one dish. Marshmallows on one side, pecan streusel on the other means nobody leaves the table disappointed.

It is also one of the most make-ahead friendly Thanksgiving sweet potatoes you can serve, which frees up precious oven time on the big day. Thanksgiving is Thursday, November 26, 2026, so you can roast and mash the potatoes as early as Monday, assemble the filling in the baking dish on Tuesday or Wednesday, and simply add the topping and bake on Thursday while everything else comes together. Nothing about this recipe is fussy, and it forgives small changes in timing.

Ingredients You Will Need

Here is what goes into the filling and toppings, plus why each ingredient matters. Exact amounts are in the recipe card.

• Sweet potatoes: Choose orange-fleshed varieties like Garnet or Jewel, often labeled yams in US stores. About 3 1/2 pounds gives you roughly 4 cups mashed.
• Butter: Unsalted butter adds richness and lets you control the salt.
• Brown sugar: Just 1/3 cup adds molasses depth; the potatoes supply most of the sweetness.
• Milk and eggs: Whole milk loosens the mash and the eggs set it into a fluffy casserole.
• Vanilla and spices: Pure vanilla extract, cinnamon, nutmeg, a little ginger and salt.
• Mini marshmallows: They melt and toast more evenly than large ones.
• Pecan streusel (optional): Chopped pecans, brown sugar, flour and melted butter.

Roasting vs. Boiling Sweet Potatoes

How to Make Sweet Potato Casserole with Marshmallows

Heat the oven to 400°F (205°C) and line a rimmed baking sheet with foil or parchment to catch the sticky juices.

1. Roast the sweet potatoes. Scrub and pierce each sweet potato several times with a fork. Roast on the lined sheet for 50 to 60 minutes until completely soft when squeezed. Let cool until you can handle them.
2. Lower the oven. Reduce the oven temperature to 350°F (175°C) and butter a 9×13-inch or 3-quart baking dish.
3. Mash the filling. Scoop the flesh into a large bowl and discard the skins. Add the melted butter, brown sugar, milk, vanilla, cinnamon, nutmeg, ginger and salt, and mash or beat with a hand mixer until smooth.
4. Add the eggs. Once the mixture is no longer hot, beat in the eggs until fully combined and fluffy.
5. Bake the base. Spread the filling evenly in the prepared dish and bake uncovered for 25 minutes, until the edges are set.
6. Add the marshmallows. Scatter the mini marshmallows over the top in an even layer, or over half the dish if you are using the pecan streusel on the other half.
7. Toast and serve. Bake 8 to 10 minutes more until the marshmallows are puffed and golden. For deeper color, broil for 30 to 60 seconds, watching constantly.

Let the casserole stand for 5 minutes before serving. The marshmallows are extremely hot straight from the oven, so give little ones a moment before they dig in. If your oven is busy with the turkey, you can bake the filling earlier in the day, then add the marshmallows and toast them in the final minutes while the turkey rests and the gravy simmers.

Marshmallow or Pecan Streusel? Make It Half and Half

If your table is divided like mine, a half and half topping is the easiest peace treaty on Thanksgiving. The streusel needs a little longer in the oven than the marshmallows, so it goes on at the start.

1. Make the streusel. Stir together 1/2 cup chopped pecans, 1/4 cup brown sugar, 2 tablespoons flour, a pinch of cinnamon and 2 tablespoons melted butter until clumpy.
2. Top half the dish. Sprinkle the streusel over one half of the filling before the first 25-minute bake.
3. Add marshmallows later. Scatter 1 1/2 cups mini marshmallows over the other half for the final 8 to 10 minutes.

Want the whole dish nutty? Double the streusel, spread it over the entire casserole, and bake for 30 to 35 minutes total. This version of sweet potato casserole with pecans is a little less sweet and has a wonderful buttery crunch.

Tips for the Best Thanksgiving Sweet Potatoes

• Pick similar-size potatoes. They roast evenly and finish at the same time.
• Use a hand mixer for silky texture. A potato masher leaves a more rustic, slightly chunky filling; both are delicious.
• Cool before adding eggs. Very hot potatoes can scramble the eggs.
• Watch the broiler. Marshmallows go from golden to burnt in seconds.
• Taste before baking. Sweet potatoes vary, so adjust sugar and salt before the eggs go in.
• Spread the marshmallows in one layer. Piling them up means the top ones scorch while the bottom ones stay pale and sticky.
• Buy extra marshmallows. Someone always sneaks a handful, and a fresh batch is handy for topping reheated leftovers.

Serve it alongside my from scratch green bean casserole and a bowl of garlic mashed potatoes for Thanksgiving for a classic spread, and save room for frosted pumpkin bars at dessert time. Browse all my holiday side dishes for even more ideas.

What to Serve With Sweet Potato Casserole

Sweet potato casserole sits right on the line between side dish and dessert, so it shines next to savory, salty mains. Roast turkey is the obvious partner, but it is just as good with glazed ham, roast chicken or pork loin cooked to 145°F (63°C) with a short rest.

To balance the sweetness on the plate, add something green and something tangy. A crisp salad with a sharp vinaigrette, roasted Brussels sprouts, or cranberry sauce all cut through the richness beautifully. Savory stuffing, buttery dinner rolls and a creamy vegetable side complete the menu.

If you are hosting a smaller Friendsgiving, halve the recipe and bake it in an 8×8-inch dish for 20 minutes before adding the marshmallows. It also makes a cozy Sunday supper side in the weeks after the holiday, when sweet potatoes are still inexpensive and at their best.

Easy Variations

• Orange zest: Add the zest of one orange and replace 2 tablespoons of the milk with fresh orange juice for a bright, citrusy filling.
• Bourbon: Stir 2 tablespoons bourbon into the filling for a grown-up, caramel-like flavor.
• Less sweet: Skip the brown sugar in the filling and rely on the topping for sweetness.
• Cornflake crunch: Toss 2 cups lightly crushed cornflakes with 3 tablespoons melted butter and 2 tablespoons brown sugar for a crunchy topping.
• Dairy-free: Use plant-based butter and unsweetened oat or almond milk.

Common Mistakes and How to Fix Them

Make Ahead, Storage and Reheating

Roast and mash the sweet potatoes up to 3 days ahead, or fully assemble the filling in the baking dish up to 2 days ahead. Cover and refrigerate without the toppings, then bake straight from the fridge, adding about 10 minutes to the first bake. Because the filling contains eggs and dairy, follow the USDA guidance on leftovers and food safety and refrigerate leftovers within 2 hours.

Leftovers keep covered in the fridge for 3 to 4 days. Reheat covered at 350°F (175°C) for 15 to 20 minutes, or microwave individual portions. The un-topped filling freezes well for up to 3 months; thaw overnight in the refrigerator and add fresh marshmallows or streusel before baking.

Frequently Asked Questions

Ready to cook? Here is the full printable sweet potato casserole with marshmallows recipe with exact measurements and estimated nutrition.

Sweet Potato Casserole with Marshmallows

Roasted sweet potatoes whipped with butter, brown sugar, vanilla and warm spices, baked under toasted marshmallows with an optional pecan streusel half.

Print Recipe Pin Recipe

Prep Time 20 minutes mins

Cook Time 35 minutes mins

Roast sweet potatoes 1 hour hr

Total Time 1 hour hr 55 minutes mins

Servings: 10 servings

Course: Side Dish

Cuisine: American

Calories: 275

Ingredients Method Notes

Ingredients

  

Sweet potato filling

• 3 1/2 pounds orange sweet potatoes about 5 medium (1.6 kg)
• 4 tablespoons unsalted butter melted (56 g)
• 1/3 cup packed brown sugar (70 g)
• 1/2 cup whole milk (120 ml)
• 2 large eggs
• 1 teaspoon pure vanilla extract
• 1 teaspoon ground cinnamon
• 1/4 teaspoon ground nutmeg
• 1/4 teaspoon ground ginger
• 1/2 teaspoon salt

Marshmallow topping

• 3 cups mini marshmallows use 1 1/2 cups if doing half pecan (150 g)

Optional pecan streusel for half the dish

• 1/2 cup pecans chopped (55 g)
• 1/4 cup packed brown sugar (50 g)
• 2 tablespoons all-purpose flour
• 1 pinch ground cinnamon
• 2 tablespoons unsalted butter melted

Method

 

1. Heat the oven to 400°F (205°C). Pierce the sweet potatoes with a fork and roast on a lined baking sheet for 50 to 60 minutes until very soft. Cool slightly.
2. Reduce the oven to 350°F (175°C) and butter a 9×13-inch baking dish.
3. Scoop the sweet potato flesh into a large bowl. Add the melted butter, brown sugar, milk, vanilla, cinnamon, nutmeg, ginger and salt, and beat until smooth.
4. When the mixture is warm but not hot, beat in the eggs until fluffy. Spread evenly in the baking dish.
5. If using the pecan streusel, stir the pecans, brown sugar, flour, cinnamon and melted butter together and sprinkle over half of the filling.
6. Bake uncovered for 25 minutes until the edges are set.
7. Scatter the marshmallows over the top (or the uncovered half) and bake 8 to 10 minutes more until puffed and golden. Broil 30 to 60 seconds for deeper color if desired, watching closely.
8. Let stand 5 minutes before serving.

Notes

Make ahead: Assemble the filling up to 2 days ahead and refrigerate; add toppings and about 10 extra minutes to the first bake.

Canned option: Use two 29-ounce cans of sweet potatoes, drained, and reduce the brown sugar to 2 tablespoons.

Nutrition is an estimate per serving for the full marshmallow version without the pecan streusel.

I hope this sweet potato casserole brings a little extra joy to your holiday table, whichever topping wins at your house. If you make it, please leave a comment and a star rating below and tell me whether your family is team marshmallow or team pecan!