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Sweet Potato Casserole with Marshmallow Fluff and Pecan-Streusel

This year I found my favorite sweet potato and marshmallow casserole recipe, featuring a sweet and perhaps surprising addition of jarred marshmallow fluff. Using marshmallow fluff gives an ultra gooey marshmallow topping, as opposed to using regular marshmallows, which tend to deflate and look a bit sad after baking.

Besides how great and fluffy it looks, I much prefer the taste of fluff as well. The topping holds up well in the oven and has a smooth, gooey consistency and wonderful flavor. I don’t think I’ll ever be going back to normal marshmallows after trying this recipe.

Sweet Potato Casserole with Marshmallow Fluff & Pecan-Streusel
Sweet Potato Casserole with Marshmallow & Pecan-Streusel

Sweet Potato Casserole with Marshmallow Fluff & Pecan-Streusel

Delicious sweet potatoes mashed and topped with gooey marshmallow fluff and a pecan streusel.
5 from 1 vote
Prep Time 1 hour
Cook Time 1 day 30 minutes
Total Time 1 day 1 hour 30 minutes
Course Side Dish
Cuisine American
Servings 12
Calories 321 kcal


  • Baking Sheet
  • Parchment Paper Sheets
  • 9 Inch Square Baking Pan


  • 4 medium sweet potatoes (about 16 ounces total)
  • 1/2 cup brown sugar
  • 1 cup whole milk
  • 2 whole eggs
  • 1 teaspoon vanilla extract
  • 1 teaspoon salt
  • 1 (13 oz.) large jar Jet-puffed marshmallow creme

For the topping:

  • 1/2 cup brown sugar
  • 1/2 cup pecans finely chopped
  • 1/3 cup flour
  • 3 Tbsp. butter melted


Cook the sweet potatoes:

  • Preheat the oven to 375-f degrees. Wash 4 medium sweet potatoes and bake them on a foil or parchment lined baking sheet until fork tender, about 1 hour. When they cool enough, scrape out the potatoes into a large bowl and discard the skins.

Prepare the casserole:

  • Preheat the oven to 400-f degrees. Add the brown sugar, milk, eggs, vanilla extract and salt to the sweet potatoes. Mash the mixture with a fork, leaving a few chunks for texture if you like.

Prepare the streusel:

  • In a separate bowl, mix the 1/2 cup brown sugar, 1/2 cup chopped pecans, 1/3 cup flour and 3 Tbsp. melted butter. Use a fork to mix thoroughly.

Finish assembling:

  • Spread the mashed sweet potato mixture into a lightly sprayed 9-inch square baking dish. Add marshmallow fluff, then sprinkle the streusel mixture over the top.
  • Bake for 30 minutes, or until golden brown. Remove from oven promptly – I have learned from experience that keeping it in there for an overly long time will affect the fluff.



Calories: 321kcalCarbohydrates: 64gProtein: 4gFat: 7gSaturated Fat: 3gPolyunsaturated Fat: 1gMonounsaturated Fat: 3gTrans Fat: 1gCholesterol: 37mgSodium: 286mgPotassium: 337mgFiber: 3gSugar: 41gVitamin A: 10855IUVitamin C: 2mgCalcium: 69mgIron: 1mg
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Recipe Rating


  1. I make a sweet potato pie with marshmallows, and hate when they disappear. I never thought to use fluff. The pecan streusel topping just puts it over the top…Pinning this!

    1. Yeah I hate when they disappear as well, along with the texture the melted marshmallows has. The fluff is great, although a tad tricky to work with, but the payoff is worth it.

  2. Oh wow, this looks good! It's so much like what Grandma Sanchez makes for Thanksgiving. Thanks for sharing on Recipe Sharing Monday! HUGS!

    1. I think you could do that Cassie, it would just take longer to warm up since you are starting with cold sweet potatoes. So I would consider covering the dish if it gets overly browned. Keep an eye on it and cover if needed. πŸ™‚

    1. It might take a little bit longer but you should check on it at the called for time and see what you think.

  3. I just made this for dinner and it is awesome! I have been vegetarian/vegan for over two years and I tend to fall into a root after a while. I think your blog has just save me from one. I feel like buying a bunch of sweet potatoes in my next visit to the farmers market!

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  4. Can I substitute canned yams for the sweet potatoes, and do you know how many cans are equivalent to 4 sweet potatoes?

    1. Sarah – I think you could but I haven't tried it personally. You would have to mash the canned yams up, either by hand or by food processor. I haven't bought them canned before so I can't speak for how many cans equals 4 sweet potatoes. Google is your friend though, I would try searching for however many ounces = how many sweet potatoes and see what comes up. Good luck!

  5. The first time I made this, the fluff and streusel ended up burning in the oven, so this time around, I baked the potatoes first and then added the fluff and streusel afterwards, right before serving. Everyone loved it! Thanks for sharing!

    1. That's interesting. I've made this twice and not had it come close to burning. You might try sometime putting an oven safe thermometer in your oven to see if it runs hot. I had an oven a few years ago that burned a lot of stuff, and it ended up that it ran on average 50-100 degrees hotter than what it said. Crazy! Anyhow, I'm glad it turned out well on the second time around. πŸ™‚ I appreciate the feedback.

    1. You could but the fluff is much better in my opinion. It retains the fluffiness whereas mini marshmallows will melt and dissolve.

  6. This stuff is amazing! I've been making it for the last 3 Thanksgiving's and it continues to get requested again. (Only thing I changed was to microwave the potatoes since my oven is usually in use.)

    1. Glad to hear that. I make it every year as well. This year I skipped the streusel topping and just did the marshmallow fluff. It was really delicious, smooth and creamy. I appreciate your feedback. Happy Thanksgiving!

    1. Probably – But If I were doing that I would still prepare the sweet potatoes in the oven first πŸ™‚