Make Ahead

Sweet Potato Casserole with Brown Sugar Fluff

October 28, 2015
1 Ratings
Photo by Ashley Rodriguez
  • Serves 8 to 10
Author Notes

The wispy peaks and valleys of the homemade fluff give this side dish drama and intrigue that mini marshmallows (which is our traditional topping) just can’t. If you already have a favorite recipe for the base of the casserole, you can swap that in for mine here and just top your classic with the brown sugar fluff. —Ashley Rodriguez

What You'll Need
  • 3 pounds yams
  • 1/2 stick butter, softened
  • 1/4 cup plus 2/3 cup dark brown sugar, divided
  • 1/2 teaspoon plus 1/4 teaspoon salt, divided
  • Pepper
  • 1/2 cup milk
  • 2 eggs
  • 3 egg whites
  1. Preheat your oven to 400° F. Place the yams on a baking sheet and roast in the oven until very tender, about 1 hour. Let cool, then remove skin with a paring knife. Cut yams into 1-inch chunks and place in the bowl of a food processor.
  2. Process the yams until a smooth purée forms. To that, add the butter, 1/4 cup brown sugar, 1/2 teaspoon salt, cinnamon, and a few grinds of pepper. Pulse that together, then taste and adjust the seasoning.
  3. Add the milk and the 2 whole eggs and process until smooth. Transfer the mixture to a baking dish.
  4. Bake for 30 to 40 minutes, until slightly puffed.
  5. For the marshmallow fluff: Make a double boiler by bringing a small pot of water to a simmer, then placing the bowl of your stand mixer or another large stainless steel bowl atop the water.
  6. Add the 3 egg whites, remaining 2/3 cup brown sugar, and remaining 1/4 teaspoon salt and whisk continuously until the sugar dissolves and the liquid is warm to the touch.
  7. Transfer the bowl from the stovetop to your stand mixer and use the whisk attachment to whip the whites on medium-high speed until it turns glossy with stiff peaks, about 5 to 8 minutes. (Use a hand-held mixer if you do not have a stand mixer.)
  8. Once the casserole has finished baking, use a rubber spatula to cover the yam mixture with the fluff. Use the back of the spatula create dramatic peaks. This will give you a nice variation in color and texture once the dish is baked.
  9. Return to the oven for 5 to 7 minutes, or until the marshmallow fluff starts to turn golden and the fluffy peaks are just shy of burnt.

See what other Food52ers are saying.

  • Andrew Morgan
    Andrew Morgan
  • Jodi Mendelson
    Jodi Mendelson
  • BrettyJax
  • Sarah Jampel
    Sarah Jampel
Author of Date Night In (2015) and creator of the blog, Not Without Salt.

11 Reviews

Andrew M. November 17, 2018
I made this three times last year, and will be making it again this year.
In terms if making ahead, I’ve made it all in one go, made it by roasting the potatoes then holding them in the fridge overnight, and by making the casserole and holding it in the fridge but making the merengue before serving. All three worked, but reheating the full casserole was a little drier.
This is amazing over the next few days, but the merengue tends to leak excess sugar which isn’t super attractive, so I’d suggest making that part day of.
Jodi M. November 11, 2016
Visiting this year. Can I make in the am and reheat when I get to the meal? Should I keep the fluff separate and just put on to reheat...will it stay? Or just make it and then reheat the whole thing?
BrettyJax November 24, 2015
Looks so yummy! Does anyone know if the fluff turns out meringuey or more like marshmallow?
Dana M. November 26, 2015
Just made this, it's definitely more like meringue. But really good and different!
jennifer M. November 21, 2015
how much cinnamon?
tamae November 18, 2015
Can the fluff be made in advance?
meagan October 31, 2015
Very interested in making this but have similar questions. I think that the eggs and milk are added to the casserole in step 3 and then in step 5 the "fluff"/ egg whites is mixed in a separate bowl (maybe on the stove) ??
Sarah J. November 1, 2015
Sorry for the confusion! Seems that a step went missing during our upload process. Check back now—I hope the extra step clarifies things!
meagan November 1, 2015
great - I will give it a try
Sara October 30, 2015
Ashley, it looks delicious, I must try it! Although, as Caitlin, I would also like some clarification about steps 3 through 5. Thank you.
Caitlin October 29, 2015
Steps 3 through 5 are a little confusing. Unclear whether the milk and eggs are being mixed into the yams or started on the stove. Further unclear on if the egg whites are being cooked on the stove top or mixed into casserole.