This Southern marshmallow sweet potato casserole is the kind of side dish that always earns a spot on my holiday table. The filling is smooth and creamy with warm spice, and the top gets that gooey toasted marshmallow layer that makes it feel a little special.
I like this version because it stays very classic and dependable. The sweet potatoes are buttery, gently cinnamon-spiced, and the texture is more like a soft mash than a stiff sliceable bake.
It’s one of my favorite Thanksgiving sweet potato sides, but I also make it for potlucks and Sunday dinners when I want an easy, familiar dish that plays well with ham or turkey.
Why You’ll Love This Recipe
Holiday Worthy: It looks right at home on a Thanksgiving table, but it’s simple enough for any cozy dinner where you want a classic Southern side.
Soft and Creamy: The filling bakes up smooth and spoonable, more like a rich sweet potato mash than a dense casserole.
That Marshmallow Top: Mini marshmallows melt and toast into a sticky, golden layer that makes the whole dish feel extra comforting.
Simple Ingredients: Everything here is easy to find, and you probably already have the spices and vanilla in your pantry.
Customizable: Add pecans for crunch, swap in evaporated milk for a richer texture, or keep it nut-free for picky eaters.
Ingredients You’ll Need
Sweet Potato Filling
- Sweet potatoes: I use orange-fleshed sweet potatoes (often labeled yams). Fresh is best here, and I like peeling them so the mash stays really smooth.
- Unsalted butter: Melted butter mixes in easily and gives the filling that classic casserole richness. If you only have salted butter, just go a little lighter on the added salt.
- Light brown sugar: This gives that cozy caramel-like sweetness. Dark brown sugar works too if you want it a touch deeper.
- Whole milk: Whole milk makes a creamier mash. Evaporated milk is great if you like it richer, and dairy-free milk works if that’s what you keep on hand.
- Eggs: The eggs help the filling set up so it’s not loose and runny. Bring them to room temp if you remember, but it’s not a dealbreaker.
- Vanilla extract: Don’t skip it. It rounds out the sweetness and makes it taste more like a true holiday sweet potato casserole.
- Ground cinnamon: Classic and simple. If your cinnamon is older, this is a good time to replace it.
- Ground nutmeg: A little goes a long way, and it really matters here. Freshly grated is nice, but pre-ground is totally fine.
- Kosher salt: Sweet potatoes need salt. It keeps the filling from tasting flat.
Topping
- Mini marshmallows: Minis melt more evenly than big marshmallows, and you get a better toasted layer across the whole top.
- Pecans: Optional, but I like the crunch. Chopped is easiest for serving so you don’t end up with big pieces pulling marshmallow off the top.
- Nonstick spray or butter: Greasing the dish makes serving much easier, especially once the sugar cools down and wants to cling to the pan.
Recipe Instructions
- Preheat the oven: Heat the oven to 350°F.
- Grease the dish: Grease a 9 x 13-inch baking dish with nonstick spray or a little butter.
- Boil the sweet potatoes: Add the sweet potato chunks to a large pot of salted water and boil until very tender, about 12 to 18 minutes.
- Drain the potatoes: Drain well, then let them sit in the colander for a minute or two so excess water steams off.
- Mash: Mash the sweet potatoes until smooth. A potato masher works, or use a hand mixer if you want it extra silky.
- Mix the filling: Stir in the melted butter, brown sugar, milk, eggs, vanilla, cinnamon, nutmeg, and salt until evenly combined.
- Spread in the dish: Spoon the mixture into the baking dish and smooth the top.
- Bake: Bake uncovered for 20 minutes, until hot throughout.
- Add the topping: Remove the dish from the oven and cover the top evenly with mini marshmallows. Sprinkle with chopped pecans if using.
- Finish baking: Return to the oven for 8 to 10 minutes, until the marshmallows are puffed and lightly golden.
- Rest: Let the casserole rest for 5 to 10 minutes before serving.
Some of my tips!
This is the part that really makes a difference. If you only read one section, make it this one because this is where I share the little trick that helps the recipe turn out so well.
Recipe Tips & Tricks
Drain the sweet potatoes really well. Extra water is the fastest way to end up with a loose filling. I usually let them steam-dry in the colander for a minute before mashing.
Roast them if you want deeper flavor. Roasting concentrates the sweet potato flavor and makes the casserole taste a little richer. Just scoop out the flesh, then mash as usual.
Use a hand mixer for the smoothest texture. If you like a super creamy filling, a quick mix makes it more uniform. Just don’t whip it forever—stop once it’s smooth.
Watch the marshmallows closely. They can go from golden to too dark quickly. If they brown too fast, tent the dish loosely with foil or move it to a lower oven rack.
Add a small flavor twist if you want. A little maple syrup or some orange zest works nicely with the cinnamon and nutmeg. Keep it light so it still tastes like the classic.
Make some touches!
There are plenty of easy ways to serve this depending on the occasion. Keep it simple, or add a few small touches to make it feel a little more special.
Serving Suggestions
- Turkey or ham: This is a natural match for roast turkey, baked ham, or smoked turkey breast. It’s also great next to gravy-heavy plates.
- Green veggies: I like serving this with green beans, Brussels sprouts, or a simple sautéed kale. Something a little bitter or garlicky is nice with the sweetness.
- Classic holiday sides: Add stuffing, mac and cheese, or cornbread dressing and you’ve got the whole Southern spread. This casserole fits right in.
- Cranberry sauce: A spoonful of cranberry sauce on the same plate is a good idea. That tart bite breaks things up.
Save it for later
This section covers how to store leftovers and what parts of the recipe you can prepare ahead of time.
Storage and Make Ahead
Store leftovers covered in the fridge for up to 4 days. Reheat individual portions in the microwave, or warm the whole dish in the oven until heated through.
You can make this recipe ahead by mixing the sweet potato filling and spreading it in the baking dish, then covering and refrigerating it. I usually wait to add the marshmallows until the day I bake it.
If you’re baking it straight from the fridge, plan on a few extra minutes for the first bake so the center gets hot. Then add the marshmallows and finish as usual.
If you want to freeze it, I find it works best to freeze the baked sweet potato base without marshmallows. Thaw in the fridge overnight, warm it through, then add marshmallows at the end.
A few quick answers
This section covers a few extra details that may help before you head to the recipe card.
Recipe FAQs
Can I roast the sweet potatoes instead of boiling?
Yes, and it’s a nice upgrade if you have the time. Roast them until very tender, scoop out the flesh, then mash and mix the filling as written.
Can I use canned sweet potatoes?
You can, especially in a pinch, but the texture is usually softer and a little wetter. If you do it, drain them well and expect the flavor to be slightly less “fresh sweet potato” than using whole potatoes.
How do I keep the casserole from being runny?
Two things matter most: draining the cooked sweet potatoes well and using enough eggs to help it set. Also make sure the casserole is fully hot throughout before you add the marshmallows.
Can I make this without marshmallows?
Definitely. You can leave it plain, or add pecans on top for some crunch. If you want a different topping altogether, a brown sugar–butter–flour streusel is also good on sweet potato casserole.
Can I make it dairy-free?
Yes. Use a dairy-free milk you like and swap the butter for a dairy-free butter alternative. The casserole will still bake up nicely, just a little less rich.
You might also like
Before you go, take a look at a few other recipes below the recipe card. They use similar ingredients in a different way and are worth saving too.
MORE DINNER RECIPES TO TRY
Southern Marshmallow Sweet Potato Side Dish
INGREDIENTS
Sweet Potato Filling
- 4 lb sweet potatoes peeled and cut into chunks
- 6 tbsp unsalted butter melted
- 1 3 cup packed light brown sugar
- 1 2 cup whole milk
- 2 large eggs
- 1 tsp vanilla extract
- 1 tsp ground cinnamon
- 1 4 tsp ground nutmeg
- 1 2 tsp kosher salt.
Topping
- 3 cups mini marshmallows
- 1 2 cup chopped pecans optional
- nonstick spray or 1 tsp butter for greasing dish.
INSTRUCTIONS
Cook and Mash
- heat oven to 350 F
- grease a 9 by 13 inch baking dish
- boil sweet potatoes in salted water until very tender 12 to 18 minutes
- drain well and mash until smooth
- stir in melted butter brown sugar milk eggs vanilla cinnamon nutmeg and salt until evenly combined
- spread mixture in baking dish and smooth the top.
Bake and Top
- bake uncovered 20 minutes until hot throughout
- remove and evenly cover with marshmallows and sprinkle pecans if using
- return to oven 8 to 10 minutes until marshmallows are puffed and lightly golden
- rest 5 to 10 minutes before serving.
