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Sweet Potato Fluff Casserole in a white baking dish plus a serving with spoon and fork.


  • Author: Denay DeGuzman
  • Total Time: 1 Hour 10 Minutes
  • Yield: 9 Servings 1x


Grace your Thanksgiving holiday table with sweet potato fluff. This delicious casserole is a photogenic side with a topping that features homemade marshmallow fluff with toasted peaks and swirls.




  • 5 sweet potatoes
  • 1/2 cup (packed) light brown sugar
  • 1/3 cup butter (plus more for buttering dish)
  • 1 1/2 teaspoons pumpkin pie spice
  • 1/2 teaspoon vanilla extract
  • 1/2 teaspoon sea salt
  • 2 tablespoons heavy cream


  • 1/3 cup water
  • 3/4 cup granulated sugar
  • 3/4 cup corn syrup
  • 1/2 cup pasteurized egg whites, room temperature *
  • 1 teaspoon cream of tartar
  • 1/4 teaspoon sea salt
  • 1 teaspoon vanilla extract

* PASTEURIZED EGG WHITES: Pasteurization kills bacteria in fresh eggs that can cause food-borne illness. Find a pourable carton of this product (like Bob Evan’s brand) at the market in the refrigerated section next to the eggs. One-half cup pasteurized egg whites is equal to separated egg whites from 4 large eggs.



RECIPE PREP: Preheat oven to 400°F. Line a rimmed baking sheet with foil. Pull out a 9×9 casserole dish. Butter the bottom and halfway up the sides.

  1. Rinse sweet potatoes. Pat them dry between paper towels. Put them on prepared baking sheet. Pierce each potato 4 times with a fork. Depending on size and thickness, bake 45 to 60 minutes or until fork tender and super soft. [See helpful multi-tasking hint below.*] Remove pan from oven.
  2. Use a lint-free cloth to grip potatoes. Slice them in half lengthwise. With a metal spoon, scoop out soft tender flesh and transfer it to a medium bowl or a food processor. Discard skins. 
  3. Put butter in a ramekin. Melt it in the microwave. Mash (or process) the hot potatoes until smooth. Add butter, sugar, pumpkin pie spice, sea salt, vanilla, and heavy cream. Mix and mash until all ingredients are fully incorporated.
  4. Transfer mashed potatoes to prepared casserole dish. With a spoon or spatula, spread the mixture into an even layer. 

*HOW TO MAKE THIS RECIPE FASTER: After sweet potatoes have been baking for 30 minutes, start assembling marshmallow fluff.


RECIPE PREP: Make triple sure mixing bowl and whip are free of grease. They must be meticulously clean. If there’s even a tiny speck of grease, it will prevent the egg whites from whipping.

  1. In a stand mixer with whisk attachment, whisk together egg whites and cream of tartar until soft peaks form, about 3 to 4 minutes. While the mixer is whisking, start prepping sugar syrup on stovetop.
  2. Combine water, granulated sugar, corn syrup and salt in a medium saucepan over medium-high heat. Bring to a boil for 8 to 10 minutes, stirring constantly. The boiling is important for thick marshmallow fluff. Don’t leave mixture unattended. It can boil over and/or burn. 
  3. With the stand mixer on medium-low setting, carefully (in a slow, thin steady stream) pour the hot sugar syrup into the egg whites. Once hot liquid is all in the bowl, add vanilla extract.
  4. Turn speed to high. Mix 7 to 8 minutes. You’ll notice ripple indentions on the surface. Keep going. We’re looking for deep creases and valleys extending vertically from the surface down to the bottom of the bowl. Mixture should be very thick and glossy. Turn off mixer. Lift metal whip. If marshmallow fluff grips the whip and forms a pointed peak at the end, the mixture is done. 


  1. Spoon dollops of marshmallow fluff over the sweet potatoes. Gently spread it into a rough layer but not all the way to the edges. Leave 1/2 inch of the orange layer visible. With the back of a spoon, form decorative peaks. Use a combination of gentle swirling and lifting motions to achieve desired look. 
  2. With a kitchen torch lightly the marshmallow fluff. It toasts super quick, so be careful. No culinary torch? No problem! See instructions for toasting without a butane torch in the “Recipe FAQ” section on this page. 

RECIPE TIP: If you want to elevate the look of the topping, transfer marshmallow fluff to a piping bag fitted with a metal tip of your choice. Pipe gorgeous swirls over the surface of the casserole.

  • Prep Time: 20 Minutes
  • Cook Time: 50 Minutes
  • Category: Side Dish
  • Method: Bake
  • Cuisine: American

Keywords: Sweet Potato Fluff, Sweet Potato Casserole