Sweet Potato Casserole with Marshmallows

ByOlivia Coleman October 25, 2025

Okay, Have You Ever Made This Before?

If you haven’t, you are in for a treat (and probably a small mess—just keeping it honest). I started making sweet potato casserole with marshmallows when my youngest insisted that Thanksgiving “tasted bland” without more sweetness, which, frankly, stung a bit since I pride myself on my mashed potatoes. But I digress. Somewhere between sampling marshmallows as a “quality check” and chatting about who gets the crispy edges, this casserole kind of turned into our unofficial family comfort food. And sometimes I make it in July because why not?

Why You’ll Fall for This — Trust Me

I usually throw this together when I’ve forgotten to make anything else for family dinners. Or when my teenager brings home a herd of friends without warning. It’s dead simple, crowd-pleasing, and the smell—wow, the smell! (There’s something magic about ooey-gooey marshmallows and sweet potato that forgives even my tendency to burn things.) And if you’ve ever fought with sticky sweet potatoes, I feel you—I’ve had a spoon get stuck in it once. Lesson learned: more butter equals less struggle.

What You’ll Need (And What I Sometimes Swap In)

4-5 medium sweet potatoes (or yams—nobody actually knows the difference; roast or boil, suit yourself)
1/2 cup brown sugar (sometimes I use maple syrup if I can’t find the sugar bag; my gran always said use Billington’s but any’ll do)
1/3 cup melted butter (honestly, I never bother measuring; more is more, right?)
1 tsp vanilla extract (or a good glug of bourbon if feeling fancy… don’t tell my kids)
1/2 cup milk (I’ve subbed in oat milk; works fine unless you’re a dairy snob)
1 tsp cinnamon—ish, sometimes heavy-handed
1/2 tsp salt (I usually forget and add after, whoops)
2 cups mini marshmallows (or big ones chopped, which is stickier but fun)
Optional: chopped pecans, dash of nutmeg, or a handful of coconut flakes (got a bit wild with coconut once, it was…interesting)

Alright, Here’s the Play-by-Play (With Side Commentary)

Preheat that oven to 375°F (190°C). Unless you forget, which I do roughly every third time.
Peel and cube the sweet potatoes. Or just split and bake them whole if you’re feeling lazy; I’ve done both, no one’s complained. Boil or roast till tender—about 20 minutes for boiling, 45 for roasting.
Drain potatoes (if boiled), and toss in a big mixing bowl. That’s where I let off steam and mash them up; smooth or chunky, your call. Sneak a taste—totally allowed.
Add brown sugar, butter, vanilla, milk, cinnamon, and salt. Mix it up till it looks creamy-ish. Don’t worry if it looks a bit weird at this stage—it always does. Actually, I find it works better if you let it cool a minute before adding egg, but I often forget eggs altogether. Oops.
Scoop mixture into a greased casserole dish. Smooth the top (or not—rustic is in). Sprinkle marshmallows all over like confetti; kids love this bit. I sometimes mix in nuts, but honestly, marshmallows steal the show.
Bake uncovered for 20 minutes until the marshmallows are golden and pillowy. Don’t walk off! Once, I came back to a charcoal marshmallow brick. Watch it like a hawk in the last 5 minutes.

Notes from the Trenches

Turns out—boiling makes for smoother casserole, but roasting brings out more flavor. Depends how lazy I’m feeling.
I read somewhere (on Simply Recipes) to add orange zest. Tried it, didn’t love. But maybe you will?
If you go heavy on the butter, expect a bit more liquid. Just let it sit a sec before serving.

Some Variations (Experiment at Your Own Risk)

I tried swapping marshmallows for a pecan-streusel once. Not bad, but honestly not as fun. My cousin prefers half marshmallow, half nuts. There’s room for all kinds here.
Coconut on top—like I mentioned—was almost really tasty, but probably needs something extra. Maybe dried cranberries? I don’t know. If you test it, let me know how it goes.
I saw a TikTok where they swirled in cream cheese. Honestly, I wasn’t a fan, but maybe I goofed a step.

You Don’t Need a Fancy Setup

All you really need is a big pot, mixing bowl, potato masher (or a big fork will do in a pinch—in my first apartment I used the bottom of a mug, true story), and a 9×13 baking dish. If you have a hand mixer, good for you. If not, work those biceps!

Sweet Potato Casserole with Marshmallows

Storing Leftovers? Let’s See If You Have Any…

This does keep in the fridge, covered, for about 3 days. (Though honestly, in my house it rarely makes it past breakfast the next day. Cold casserole and coffee? Odd, but not bad on a rainy morning.) Freezes okay, but marshmallows get a bit weird in texture after thawing—just being real.

How I Serve It (And That Extra Step I Sometimes Take)

We plop it on the table, spoon out big dollops, and sometimes pop a few extra marshmallows on top last minute. My aunt always insists on a scoop of vanilla ice cream with hers. I like it alongside turkey roast or just on its own with coffee late at night, pretending I’m doing “quality control.” Oh, and if you’re in the mood for a different cozy side, I follow this Southern Living classic sweet potato casserole sometimes for inspiration (in case you need a second opinion).

Things I Messed Up (So You Don’t Have To)

Don’t rush the marshmallow broil. I once tried to finish it under the grill for “just a minute”—big mistake. Burnt, stuck-on mess (but my dog loved it).
Forgot to grease the casserole dish. Cleaning it took longer than making the casserole did.
One time I tried microwaving it to reheat—marshmallows exploded everywhere. Oven reheating for the win.

FAQ—Real Questions, Real Quick

Can I make this ahead? Yep! Make the base, cover, and refrigerate, then bake with marshmallows right before serving. Actually, I think this tastes better the next day anyway—flavors settle in kinda nice.
Is it vegetarian? Most marshmallows aren’t (dang gelatin), but there are a couple of vegan ones out there, like Dandies, if that’s important to you.
How sweet is it? Can I cut sugar? Of course. Sometimes I halve the sugar if I’m already on a pie or two. Or swap in honey, which is a little less heavy. Maybe up the spices for more zing.
Why is my casserole runny? Could be too much milk or butter. Just bake it a little longer, or honestly, eat it with a spoon—that’s half the fun.
Do I have to use marshmallows? Absolutely not! But then it isn’t really a sweet potato casserole “with marshmallows”—and where’s the fun in that?

So give it a whirl, and don’t sweat the small stuff (or the sticky stuff). If you try something wild, tell me! I’m always up for a kitchen adventure—even if it gets a bit messy, which, come to think of it, probably makes the best stories in the end.

Olivia Coleman