This Perfect Sweet Potato Casserole with Marshmallows is a classic Thanksgiving treat that combines creamy, mashed sweet potatoes with a golden, gooey marshmallow topping. The sweet and slightly spiced potato base pairs so nicely with the crunchy and soft marshmallows melted on top, making every bite a comforting celebration of flavors and textures.
I love making this casserole because it’s always a crowd-pleaser, especially with kids around who can’t wait to get to the marshmallows. One little tip I’ve learned is to watch the marshmallows closely while baking—they turn golden quickly and you want them beautifully toasted without burning. It adds that perfect touch of sweetness and a little bit of fun to the dinner table.
My favorite way to serve this is warm, fresh out of the oven, right alongside all the savory Thanksgiving dishes. It’s like a sweet hug on the plate and somehow makes the meal feel extra special. Honestly, this dish has become a must-have in our holiday lineup, and I’m sure it will be in yours too once you try it!
Key Ingredients & Substitutions
Sweet Potatoes: The star of this dish! Choose firm, orange-fleshed sweet potatoes for the best color and natural sweetness. If you want a milder flavor, Japanese sweet potatoes work, but they’re less sweet.
Butter & Milk: These add creaminess. I use whole milk and unsalted butter, but you can swap milk for a plant-based kind to keep it dairy-free. Coconut oil is a nice butter alternative too.
Sugars: The mix of white and brown sugar balances sweetness and depth. If you prefer less sweet, reduce the granulated sugar. Maple syrup can be used instead of sugars for a nice twist.
Eggs & Spices: Eggs help bind and give a smooth texture. Cinnamon and nutmeg bring warm spice notes. Feel free to add a pinch of ginger or cloves for extra warmth.
Marshmallows: Mini marshmallows toast beautifully on top and add fun texture. If you want to skip marshmallows, a crunchy pecan crumble topping works great too.
How Do I Get the Marshmallows Perfectly Toasted without Burning?
Toasting marshmallows can be tricky because they brown fast. Here’s my simple tips:
- Bake the casserole at 350°F for about 25-30 minutes to heat through and soften the marshmallows.
- For that golden brown color, switch to the oven’s broiler for 1-2 minutes at the very end.
- Watch closely the entire time under the broiler—it just takes a moment for marshmallows to go from golden to burnt.
- Alternatively, use a kitchen torch to toast marshmallows evenly and control browning.
This two-step method gives you a soft, warm interior with a beautiful toasted top that’s just right for this dish!
Equipment You’ll Need
- Large pot – I use it to boil the sweet potatoes easily and quickly.
- Mixing bowl – perfect for mashing and combining all the ingredients smoothly.
- 9×13-inch baking dish – this size fits the casserole well and bakes evenly.
- Potato masher or fork – helps mash the cooked sweet potatoes until smooth.
- Measuring cups and spoons – for accurate ingredients, especially sugars and spices.
- Oven-proof spatula or spoon – for spreading the sweet potato mixture evenly.
- Optional: Broiler or kitchen torch – to toast the marshmallows perfectly without burning.
Flavor Variations & Add-Ins
- Use brown sugar and cinnamon with chopped pecans for a crunchy topping—adds texture and flavor.
- Swirl in canned pumpkin or apple cider for a different seasonal twist.
- Mix in chopped cooked apples or pears for extra sweetness and fruitiness.
- Replace marshmallows with a streusel topping made of oats, butter, and brown sugar for a crunchier finish.
Perfect Sweet Potato Casserole for Thanksgiving with Marshmallows
Ingredients You’ll Need:
Main Ingredients:
- 4 large sweet potatoes (about 3 pounds), peeled and cubed
- ½ cup granulated sugar
- ½ cup packed light brown sugar
- ½ cup unsalted butter, melted
- ½ cup whole milk
- 2 large eggs
- 1 teaspoon vanilla extract
- ½ teaspoon salt
- ½ teaspoon ground cinnamon
- ¼ teaspoon ground nutmeg
- 2 cups mini marshmallows
- 1 cup chopped pecans (optional, for topping under marshmallows)
Time You’ll Need:
This recipe takes about 15-20 minutes to prep, 15-20 minutes to boil the potatoes, and 25-30 minutes baking time. Overall, expect around 1 hour from start to finish.
Step-by-Step Instructions:
1. Prep and Cook Sweet Potatoes:
Preheat your oven to 350°F (175°C) and lightly grease a 9×13-inch baking dish. Put the peeled and cubed sweet potatoes into a large pot, cover them with water, and bring to a boil. Cook until tender, about 15-20 minutes.
2. Mash and Mix:
Drain the cooked sweet potatoes really well, then mash them in a large bowl until smooth. Add both sugars, melted butter, milk, eggs, vanilla extract, salt, cinnamon, and nutmeg. Mix everything together until fully combined.
3. Assemble the Casserole:
Spread the sweet potato mixture evenly in the prepared baking dish. If you’d like, sprinkle the chopped pecans evenly on top of the sweet potato layer. Then, cover the entire surface with mini marshmallows.
4. Bake and Toast the Marshmallows:
Put the casserole in the oven and bake for 25-30 minutes until it’s heated through and the marshmallows are golden brown. For extra browning, switch your oven to the broiler for 1-2 minutes but watch it carefully so the marshmallows don’t burn.
5. Serve and Enjoy:
Remove the casserole from the oven and let it cool for a few minutes before serving warm. Enjoy your delicious, creamy sweet potato casserole topped with toasty, gooey marshmallows!
Can I Make Sweet Potato Casserole Ahead of Time?
Yes! You can prepare the casserole up to step 7, cover it tightly, and refrigerate for up to 24 hours. When ready to serve, add the marshmallows and bake as directed.
Can I Use Frozen Sweet Potatoes for This Recipe?
Absolutely! Just thaw them completely and drain any excess moisture before mashing. This helps keep the casserole from becoming watery.
What Can I Use Instead of Marshmallows?
If you prefer to skip marshmallows, try a crunchy pecan and brown sugar streusel topping for a delicious alternative.
How Should I Store Leftovers?
Store any leftovers in an airtight container in the refrigerator for up to 3 days. Reheat gently in the oven or microwave before serving.