Description
This Sweet Potato Casserole with Marshmallows and Oat Streusel is a comforting and festive side dish perfect for holiday gatherings. Made with tender mashed sweet potatoes, topped with a gooey layer of mini marshmallows and a crunchy oat streusel, this casserole combines creamy, sweet, and crispy textures for a truly irresistible treat.
Ingredients
Scale
Sweet Potatoes
- 3 medium sweet potatoes
- 1 teaspoon salt
- 2 tablespoons butter
- 1/4 cup milk
- 1 teaspoon pumpkin pie spice
Oat Streusel Topping
- 4 tablespoons butter, cold
- 1/4 cup brown sugar
- 1/4 cup flour
- 1/4 cup rolled/old fashioned oats
- 1/2 teaspoon baking powder
- 1/2 teaspoon pumpkin pie spice
- Pinch of salt
Additional
- 3 cups mini marshmallows
Instructions
- Prepare Sweet Potatoes: Peel and slice the sweet potatoes into 1-inch rounds. Place the sliced potatoes and 1 teaspoon of salt into a large pot and cover with cold water.
- Cook Potatoes: Bring the pot to a boil over high heat, cover, and cook the potatoes for 20-25 minutes or until they are tender and easily pierced with a fork.
- Drain and Steam Dry: Carefully drain the water from the pot. Return the pot to medium heat and cook uncovered for 1 to 2 minutes to evaporate excess moisture from the potatoes.
- Mash Potatoes: Remove the pot from heat. Add 2 tablespoons butter, 1/4 cup milk, and 1 teaspoon pumpkin pie spice to the potatoes. Gently mash until smooth. Set aside or store in an airtight container if preparing ahead.
- Make Streusel Topping: Cut cold butter into small marble-sized pieces and combine with brown sugar, flour, oats, baking powder, pumpkin pie spice, and a pinch of salt in a medium bowl.
- Mix Streusel: Using two forks, a pastry cutter, or fingers, cut the butter into the dry ingredients until coarse crumbs form about the size of large peas. Store in an airtight container if making ahead.
- Preheat Oven: Preheat the oven to 350ºF (175ºC) and grease a 2½ quart baking dish.
- Assemble Casserole: Spread the mashed sweet potatoes evenly and smoothly in the prepared baking dish.
- Add Marshmallows and Streusel: Layer the mini marshmallows evenly over the sweet potatoes, then sprinkle the oat streusel topping gently on top of the marshmallows.
- Bake: Bake in the preheated oven for 18-20 minutes, watching closely to prevent the marshmallows from over-browning.
- Rest: Remove from oven and let sit for at least 10 minutes to set, ensuring the butter and marshmallows solidify for an ideal texture.
- Make Ahead Tips: Prepare and store each component separately up to 2 days ahead. Store mashed potatoes in the baking dish in the fridge, keep streusel in a sealed container, and pre-measure marshmallows in a separate bag. Before baking, remove potatoes from fridge 30 minutes prior, then layer marshmallows and streusel just before baking as directed.
Notes
- For best results, use a 2½ quart baking dish but a similar size dish will work.
- Watch the marshmallows carefully during baking to prevent burning.
- Allowing the casserole to rest after baking improves texture and makes serving easier.
- This dish can be prepared up to two days in advance for convenience.
- Use old-fashioned rolled oats for the best streusel texture.
