Easy Sweet Potato Casserole with Marshmallows
Sweet potato casserole with a toasted marshmallow top is a Thanksgiving classic that can easily turn out too sweet. This version keeps the base creamy and lightly spiced, with a moderate amount of brown sugar, so the sweet potatoes still taste like sweet potatoes.
It needs one pot, one baking dish and simple pantry ingredients, and the base can be made a day ahead. The full recipe is in the card below.
Easy Sweet Potato Casserole with Marshmallows
Equipment
- Large pot
- Colander
- Potato masher or hand mixer
- 9×13-inch (3-quart) baking dish
- Instant-read thermometer
Ingredients
Sweet potato base
- 3 pounds sweet potatoes about 4 medium, peeled and cut into 1-inch cubes
- 4 tablespoons unsalted butter melted
- ⅓ cup packed light brown sugar
- ½ cup whole milk
- 2 large eggs lightly beaten
- 1 teaspoon vanilla extract
- 1 teaspoon ground cinnamon
- ½ teaspoon salt
Topping
- 4 cups mini marshmallows about 7 ounces
Instructions
- Heat the oven to 350°F (175°C). Grease a 9×13-inch baking dish.
- Put the sweet potatoes in a large pot and cover with cold water by 1 inch. Bring to a boil, then simmer for 15–20 minutes, until a fork slides in with no resistance. Drain well and return to the warm pot for 1 minute to steam off excess water.
- Mash the sweet potatoes until smooth. Add the melted butter, brown sugar, milk, vanilla, cinnamon and salt and mix well.
- Let the mixture cool for 5 minutes, then stir in the eggs until fully combined.
- Spread the mixture evenly in the baking dish. Bake uncovered for 25 minutes, until the edges are set and the center reaches 165°F (74°C).
- Scatter the marshmallows over the top in an even layer. Bake for 8–10 minutes more, until puffed and golden brown. Watch closely in the last few minutes; marshmallows burn quickly. Rest for 5 minutes before serving.
Notes
Why This Sweet Potato Casserole Works
Boiling cubed sweet potatoes is the fastest way to get them soft enough to mash, and a minute in the warm, empty pot afterward dries them out so the casserole is creamy, not watery.
The eggs give the base a soft, spoonable set, like a light pudding. Letting the mash cool for a few minutes before adding them stops the eggs from scrambling.
The marshmallows go on only after the base has baked. Added at the start, they would melt into the sweet potatoes and burn before the center is hot.
Choosing Sweet Potatoes
Choose firm sweet potatoes with smooth skin and no soft spots. Orange-fleshed varieties, often sold as yams in US stores, give the classic color and sweetness. Pale or purple-fleshed sweet potatoes are drier and less sweet, so the texture will be thicker.
Pick potatoes of similar size and cut them into even cubes so they cook at the same rate.
Healthier Sweet Potato Casserole Swaps
Sweet potato casserole is a holiday treat, but it is easy to lighten:
- Cut the brown sugar to 2 tablespoons. Sweet potatoes are sweet on their own and the marshmallows add more.
- Use 2 cups of marshmallows to dot the top instead of covering it.
- Skip the marshmallows and bake with a sprinkle of chopped pecans and a pinch of cinnamon instead.
- Use 2% milk in place of whole milk.
Making Sweet Potato Casserole Ahead
Prepare the base up to a day ahead, spread it in the baking dish, cover it and refrigerate it. Add the marshmallows only on the day you bake it, once the base is hot through. A cold dish needs a longer bake, so check the center with a thermometer before topping.
This frees up both the stovetop and your time on Thanksgiving Day, when the oven is busiest.
What to Serve with Sweet Potato Casserole
Sweet potato casserole belongs next to roast turkey and ham, and it works on a weeknight too. Serve it with our creamy Tuscan chicken or sheet pan sausage and vegetables.
On a Thanksgiving table, it sits well next to our green bean casserole, garlic mashed potatoes, crockpot mac and cheese and homemade cranberry sauce.
If you like sweet potatoes beyond the holidays, our baked chicken and sweet potato meal prep uses them in an everyday lunch.
Storage and Reheating
Store leftovers in an airtight container in the refrigerator for up to 4 days. Reheat in a covered baking dish at 350°F, or in the microwave, until hot all the way through (165°F). The marshmallows soften in the fridge but still taste good.
Sweet Potato Casserole FAQ
Can I use canned sweet potatoes? Yes. Use two 29-ounce cans of cut sweet potatoes, drained well, and skip the boiling step. Canned sweet potatoes in syrup are sweeter, so cut the brown sugar.
Can I freeze sweet potato casserole? Freeze the base without marshmallows for up to 3 months. Thaw overnight in the refrigerator, bake until the center reaches 165°F, then add the marshmallows.
Can I make it without eggs? Yes. The base will be softer and more like mashed sweet potatoes, but it still bakes well.
Why did my marshmallows burn? Usually because the oven runs hot or the dish sits on a high rack. Bake on the middle rack and start checking after 6 minutes.
