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Angled view of sweet potato casserole with marshmallows and brown butter pecan topping in a casserole dish.

Sweet Potato Casserole with Marshmallows and Brown Butter Pecan Topping


Classic Sweet Potato Casserole with Marshmallows is brought up a notch with a brown butter pecan topping. Learn my pro tips to perfect this dish.


  • 3lbs sweet potatoes
  • Olive or vegetable oil, as needed
  • 4 tbsp unsalted butter, softened at room temperature
  • ½ cup heavy cream, at room temperature
  • ¼ cup sour cream, at room temperature
  • ¼ cup light brown sugar, packed
  • Dash freshly grated nutmeg
  • Kosher salt


  • 6 tbsp unsalted butter, sliced
  • ¾ cup all-purpose flour
  • ½ cup light brown sugar, packed
  • ½ tsp kosher salt (less if using fine salt)
  • ¼ tsp ground cinnamon
  • ¾ cup pecans
  • 1 ½2 cups mini marshmallows*


  1. Heat oven: Preheat oven to 375°F.
  2. Bake sweet potatoes: Slice potatoes in half lengthwise. There is no need to peel. Place cut side down on a lined baking sheet. Coat lightly with olive oil. Bake in preheated oven for 30-45 minutes or until very tender. Leave oven on.
  3. Mash potatoes: While potatoes are still hot, press through a ricer or process through a food mill. You can also peel the potatoes and mash them with a regular masher. Do not over work or they may become gummy.
  4. Mix filling: In a large bowl, combine sweet potatoes with butter, heavy cream, sour cream, sugar, salt and nutmeg. Stir until smooth. Set aside.
  5. Brown butter: Melt butter in a saucepan over medium heat. Cook for about 6-8 minutes or until water evaporates and solids brown. Pour directly into a bowl to cool slightly.
  6. Mix topping: In another bowl, combine flour, sugar, salt and cinnamon. Rub brown sugar and flour together with your fingers to remove any lumps. Stir in browned butter. Stir in pecans. Set aside.
  7. Assemble and bake: Spread sweet potatoes in the bottom of an 8×8 inch or 9×9 inch pan. Sprinkle over pecan topping. Bake at 375°F for 20-30 minutes or until browned on top and heated through.
  8. Toast marshmallows: Top with marshmallows. Toast using a culinary blow torch or under the broiler of the oven on high. If using broiler, check for doneness every 1-2 minutes. Enjoy.


*If using my recipe for homemade marshmallows in my Hot Chocolate with Peppermint Marshmallows post, leave out the peppermint extract and red dye to make regular marshmallows. Simply cut smaller to make mini marshmallows. 

If making this for the holidays, the sweet potato filling and pecan topping can be made up to 3 days advance and refrigerated in separate containers. Assemble the day of, and extend baking time as needed to thoroughly heat refrigerated ingredients. 

  • Prep Time: 30 minutes
  • Cook Time: 30 minutes
  • Category: Side
  • Method: Baked
  • Cuisine: American


  • Serving Size: 1/12 of casserole
  • Calories: 350
  • Sugar: 22g
  • Sodium: 270mg
  • Fat: 17g
  • Saturated Fat: 8g
  • Unsaturated Fat: 9g
  • Trans Fat: 0g
  • Carbohydrates: 49g
  • Fiber: 4g
  • Protein: 4g
  • Cholesterol: 33mg

Keywords: sweet potato casserole, sweet potato casserole with pecan topping, sweet potato casserole with marshmallows, Thanksgiving