Sweet Potato Pie Bars with Marshmallow Swirl (Party-Perfect)

You want a dessert that makes people stop mid-conversation and say “Wait—what is this?” This is that dessert. Sweet Potato Pie Bars with a toasty marshmallow swirl are nostalgic, portable, and engineered to disappear faster than your New Year’s resolutions. They’ve got a buttery shortbread base, plush sweet potato filling, and a dramatic marshmallow ripple that looks like you hired a pastry chef.

You’ll slice, flex, and collect compliments like it’s your side hustle. Ready to be the MVP of the dessert table?

Why This Recipe Works

Traditional sweet potato pie is amazing, but bars make it party-perfect. They slice clean, travel well, and don’t require plates and forks for every bite.

The shortbread crust stays crisp, the filling is silky without being heavy, and the marshmallow swirl gets golden and caramelized on top.

We roast the sweet potatoes for deeper caramelized flavor (steaming or boiling? Fine. Roasting?

Superior). A mix of brown sugar, warm spices, and vanilla yields that classic pie vibe but with better structure for bars. The marshmallow swirl?

It adds sweetness and drama without overwhelming the sweet potato.

What Goes Into This Recipe – Ingredients

• For the Shortbread Crust:
  • 1 cup (2 sticks) unsalted butter, melted
  • 1/2 cup granulated sugar
  • 1/2 teaspoon fine sea salt
  • 2 cups all-purpose flour
  • 1 teaspoon vanilla extract
• For the Sweet Potato Filling:
  • 2 cups mashed roasted sweet potato (from about 2 large sweet potatoes)
  • 3/4 cup packed light brown sugar
  • 2 large eggs, room temperature
  • 1/2 cup evaporated milk (or heavy cream for extra richness)
  • 3 tablespoons unsalted butter, melted and slightly cooled
  • 1 1/2 teaspoons vanilla extract
  • 1 teaspoon ground cinnamon
  • 1/2 teaspoon ground nutmeg
  • 1/4 teaspoon ground ginger
  • 1/4 teaspoon fine sea salt
• For the Marshmallow Swirl:
  • 1 1/2 cups mini marshmallows or 1 cup marshmallow creme/fluff
  • Optional: 1 tablespoon maple syrup for thinning marshmallow creme
• To Finish:
  • Flaky sea salt, for sprinkling
  • Optional: crushed pecans or graham crumbs for garnish

Let’s Get Cooking – Instructions

1. Roast the sweet potatoes: Preheat oven to 400°F (204°C). Pierce sweet potatoes all over, place on a lined sheet, and roast 45–60 minutes until very tender. Cool, peel, and mash until smooth.Measure 2 cups.
2. Drop the oven temp: Reduce to 350°F (177°C). Line a 9×13-inch pan with parchment, leaving overhang for easy lifting.
3. Make the crust: In a bowl, whisk melted butter, sugar, salt, and vanilla. Stir in flour until a soft dough forms.Press evenly into the prepared pan. Dock lightly with a fork. Bake 12–15 minutes until set and just beginning to color.
4. Mix the filling: In a large bowl, whisk mashed sweet potato, brown sugar, eggs, evaporated milk, melted butter, vanilla, spices, and salt until silky.No lumps—smooth is the assignment.
5. Assemble and bake: Pour filling over warm crust. Tilt to level. Bake 22–28 minutes until the edges are set and the center has a slight jiggle.Don’t overbake—custard rules apply.
6. Add the marshmallow swirl:
   • If using mini marshmallows: Scatter evenly over the hot filling, then return to the oven 3–5 minutes until puffed and lightly golden. Broil 30–60 seconds if you want more toast—watch like a hawk.
   • If using marshmallow creme: Warm gently with a splash of maple syrup until spreadable. Dollop over the hot filling in 6–8 spoonfuls, then swirl with a knife.Torch or broil briefly if desired.
7. Cool completely: Let the pan cool at room temp, then chill 1–2 hours for clean slices. Yes, waiting is annoying. Yes, it’s worth it.
8. Slice and finish: Lift out using parchment.Cut into 16–20 bars. Sprinkle with flaky sea salt and optional crushed pecans or graham crumbs.

Preservation Guide

• Room temperature: Store tightly covered for up to 1 day if your kitchen is cool.
• Refrigerator: Keeps 4–5 days. The crust stays crisp if bars are fully cooled before covering.
• Freezer: Freeze uncut bars (without marshmallow topping for best texture) up to 2 months.Thaw overnight in the fridge and add marshmallow swirl fresh, then rewarm to toast.
• Reheating: For that just-baked vibe, warm individual bars at 300°F (150°C) for 8–10 minutes. If marshmallows need reviving, 1–2 minutes under the broiler works—careful, they brown fast.

What’s Great About This

• High reward, low effort: No rolling dough, no lattice, no stress. Just press, pour, bake.
• Make-ahead friendly: Bake the base and filling a day early; swirl and toast the marshmallow before serving.
• Portable and tidy: Bars = parties, picnics, potlucks.Minimal utensils, maximal applause.
• Balanced sweetness: Sweet potato earthiness keeps marshmallow from going overboard. It’s dessert, not a sugar bomb.

Pitfalls to Watch Out For

• Wet sweet potatoes: If they’re watery, the filling won’t set right. Roast instead of boil, and if needed, mash and cook off moisture in a skillet for a few minutes.
• Overbaking: When the center loses its jiggle, you’re in danger zone.Overbaked filling turns grainy—no thanks.
• Impatient slicing: Warm bars will squish and smear. Chill for clean edges. Your knife will thank you.
• Marshmallow burn: Broilers are chaotic neutral.Stay close, or you’ll go from golden to campfire ash in seconds.

Mix It Up

• Bourbon Boost: Add 1–2 tablespoons bourbon to the filling. It’s subtle, sophisticated, and yes, a little dangerous (in a good way).
• Pecan Crunch: Fold 1/2 cup toasted chopped pecans into the crust dough or sprinkle on top before toasting the marshmallow.
• Maple Twist: Swap half the brown sugar for pure maple syrup and reduce evaporated milk by 2 tablespoons.
• Chai Spice: Replace cinnamon/nutmeg/ginger with 2 teaspoons chai spice blend for a cozy cafe vibe.
• Gluten-Free: Use a 1:1 gluten-free flour blend for the crust. Add 1 tablespoon cornstarch to the filling for extra insurance.
• Dairy-Free: Use vegan butter in the crust and swap evaporated milk with full-fat coconut milk.Use dairy-free marshmallows.

FAQ

Can I use canned sweet potato or canned yams?

Yes—use plain canned sweet potato puree, not pie filling. If it’s very loose, simmer a few minutes to thicken. Avoid candied yams in syrup unless you drastically reduce the sugar (FYI, it’ll be sweet-sweet).

Do I need to blind-bake the crust?

Nope.

A quick pre-bake is enough to set the shortbread so it stays crisp under the custard-style filling. Blind-baking with weights isn’t necessary here.

How do I get perfectly smooth filling?

Use fully roasted sweet potatoes and mash while warm, or blitz the filling briefly with an immersion blender. Strain through a fine sieve if you’re extra.

Smooth filling equals luxe texture.

Can I make these a day ahead?

Absolutely. Bake and chill the bars, then add the marshmallow swirl and toast right before serving for best texture and presentation. IMO, the flavor improves overnight.

What if I don’t have evaporated milk?

Use heavy cream or half-and-half in equal measure.

Whole milk works, but the filling will be slightly lighter and less custardy.

How do I cut clean squares?

Chill the bars, then use a long sharp knife warmed under hot water and wiped dry between cuts. It’s a small step with big bakery-level results.

Can I scale this recipe?

Yes. Halve for an 8-inch square pan (start checking a few minutes earlier) or double for a sheet pan.

Keep thickness in mind—thicker layers need a few extra minutes.

The Bottom Line

These Sweet Potato Pie Bars with Marshmallow Swirl are the dessert equivalent of a mic drop: simple to make, gorgeous to serve, and impossible to stop eating. They bring cozy holiday energy any time of year, play nice at parties, and deliver that sweet-salty, creamy-crisp contrast everyone loves. Make them once, and they’ll be your signature move.

Don’t be surprised when people ask for the recipe—just smile and say, “Coming to your inbox.”