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Sweet Potato Casserole with Marshmallows and Cinnamon

Sweet potato casserole with marshmallows gets its warm flavor from cinnamon and light brown sugar, then bakes beneath a golden marshmallow topping. The mashed sweet potato filling is smooth and creamy, with a crisp, toasted finish on top.
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Prep Time 15 minutes
Cook Time 45 minutes
Cooling and resting time 15 minutes
Total Time 1 hour 15 minutes
Servings: 8 servings
Course: Side Dish
Cuisine: American
Calories: 285
Ingredients Equipment Method Notes

Ingredients
  

For the sweet potato filling
  • 3 lb sweet potatoes peeled and cut into 1-inch cubes
  • 8 cup water or enough to cover the potatoes
  • 4 tbsp unsalted butter
  • 0.33 cup light brown sugar packed
  • 0.33 cup whole milk
  • 1 egg large
  • 1 tsp ground cinnamon
  • 0.5 tsp kosher salt
For the topping
  • 2 cup mini marshmallows

Equipment

  • 1 6-quart pot
  • 1 9x13-inch baking dish

Method
 

Cook and mash the sweet potatoes
  1. Heat the oven to 350°F.
  2. Grease a 9x13-inch baking dish.
  3. Put the sweet potatoes and water in a 6-quart pot.
  4. Bring to a boil over high heat.
  5. Reduce the heat and simmer for 15 to 20 minutes, until the potatoes are fork-tender.
  6. Drain the potatoes well.
  7. Return the potatoes to the pot.
  8. Mash with the butter, brown sugar, milk, cinnamon, and salt until mostly smooth.
  9. Let the mixture cool for 5 minutes.
  10. Stir in the egg until fully combined.
Assemble and bake
  1. Spread the sweet potato mixture evenly in the prepared baking dish.
  2. Bake for 20 minutes.
  3. Scatter the marshmallows evenly over the casserole.
  4. Bake for 5 to 8 minutes, until they are golden and the center of the casserole reaches 160°F.
  5. Let the casserole rest for 10 minutes before serving.

Notes

For the smoothest filling, mash the potatoes while they’re still hot. Refrigerate leftovers for 3 to 4 days; freeze for up to 2 months. Whole milk can be swapped for unsweetened, unflavored non-dairy milk.