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Best Sweet Potato Casserole with Marshmallows
5 from 12 votes

Best Sweet Potato Casserole with Marshmallows

This Sweet Potato Casserole blends mashed sweet potatoes with butter, half-and-half, brown sugar, spices, eggs, vanilla, and salt to create a creamy base. It’s topped with a crumbly mixture of oat flour, brown sugar, cinnamon, salt, melted butter, and pecans, then finished with miniature marshmallows for a sweet, toasted crust. An optional meringue topping provides a fluffy alternative.

Prep Time
20 mins
Cook Time
35 mins
Total Time
55 mins
Servings: 12 people
Calories: 3241 kcal
Course: Side Dish
Cuisine: American

Ingredients

For the Mashed Sweet Potato Base:
  • 3 pounds sweet potato washed (about 3-4 large sweet potatoes
  • 4 tablespoons butter melted (for making it dairy-free, use dairy-free butter or coconut oil, unsalted
  • ⅓ cup half-and-half or whole milk which is full-fat. NOTE: To make it dairy-free, replace it with unsweetened soy milk or almond milk but you may have to reduce the amount of liquid slightly to not make your mashed sweet potato base watery. A full-fat liquid helps with a thick consistency and a richer flavor.
  • ½ cup light brown sugar Use Brown Swerve for a low-carb or sugar-free dish!
  • 1 teaspoon cinnamon
  • ¼ teaspoon ground nutmeg optional
  • 2 egg lightly beaten, large
  • 1 teaspoon vanilla extract pure
  • ½ teaspoon table salt
For the Topping:
  • ½ cup light brown sugar or Brown Swerve to make it sugar-free or low-carb.
  • ¾ cup oat flour , certified gluten-free. If you don't have oat flour you can make your own by grinding rolled oats in a food processor until obtaining a flour texture. NOTE: If you aren't a celiac, you may replace oat flour with ½ cup of all-purpose flour.
  • ¾ teaspoon cinnamon
  • Pinch table salt
  • 6 tablespoons butter melted (you may use coconut oil if you prefer to make it dairy-free, unsalted
  • 1 ¼ cups pecans for a nut-free casserole, use sunflower seeds instead, chopped
  • 2 cups miniature marshmallows you may replace them with the toasted meringue topping below. Or for a low-carb/sugar-free version, use sugar-free marshmallows.
Alternative Topping (Toasted Meringue):
  • 2 egg separated (yolks from whites
  • ⅛ teaspoon cream of tartar
  • ½ cup powdered sugar

Instructions

    Cup of Yum
  1. COOK THE SWEET POTATOES: You can cook them either in the microwave or boil them.
  2. To Microwave: Prick the sweet potatoes all over with a fork and place them in a microwave-safe dish. Cook them on full power for about 8-12 minutes (depending on the microwave potency) or until they turn out soft. Then, peel them by gently scrubbing the peel with a pairing knife. Alternatively, cut them lengthwise and scoop all the flesh out of the peel using a spoon or cookie scoop. Just be careful to avoid burning your hands!
  3. To Boil: Peel them first, cut them into 1-inch chunks, and place them into a pot filled with cold water (never boiling water; otherwise they won't cook evenly). Bring to a boil and let cook for about 12-15 minutes or until soft. Drain!
  4. Meanwhile, preheat the oven to 375º F. Grease a 9x13-inch baking dish with cooking spray or butter.
  5. MASH: Using a potato masher, mash the sweet potatoes and stir in melted butter, half-and-half, brown sugar, spices, eggs, vanilla, and salt until creamy and smooth.
  6. Transfer the mixture to the prepared baking dish and smooth it out evenly using a rubber spatula.
  7. PREPARE THE PECAN TOPPING: In a medium bowl, combine the brown sugar, oat flour, cinnamon, salt, melted butter, and chopped pecans. Mix them well together with a fork or using your hands until combined. Sprinkle over the top of the mashed sweet potatoes.
  8. BAKE: Bake the sweet potato casserole until heated all the way through and the topping begins to brown, about  25-30 minutes. Remove it from the oven and sprinkle it with the marshmallows.
  9. BROIL THE MASHMALLOWS: Set the oven to broil, then place the baking dish about 6-8 inches away from the top broiler heating source. Let it broil just long enough for the marshmallows to toast on top without burning. TIP: Watch it carefully!
  10. Serve it right away and enjoy!
  11. OR TOP WITH THE TOASTED MERINGUE TOPPING INSTEAD: Alternatively, If you prefer a toasted meringue topping instead of a marshmallow topping, beat the egg whites with cream of tartar in the bowl of a mixer until foamy, about 1-2 minutes. Add powdered sugar and beat again until stiff, about 1-2 minutes. Increase heat to 400 degrees F. Remove the baked sweet potato casserole from the oven, spoon the meringue on top, and bake on the top rack of the oven for an additional 6-7 minutes or until the meringue is golden brown. Serve immediately!

Notes

  • Store leftovers in an airtight container in the refrigerator for 3-4 days to maintain freshness.
  • Freeze unbaked or baked casserole without marshmallows or meringue topping in an airtight container for up to 3 months.
  • Thaw frozen casserole overnight in the refrigerator before reheating.
  • Reheat covered in the microwave just until warmed through to avoid drying out.
  • For dairy-free options, substitute butter with dairy-free alternatives and milk with unsweetened plant milks, adjusting liquid amounts as needed.
  • Oat flour can be homemade by grinding rolled oats or substituted with all-purpose flour if gluten is not a concern.
  • The optional toasted meringue topping can replace marshmallows for a lighter finish.

Nutrition Information

Calories 324.1kcal (16%) Carbohydrates 46.5g (16%) Protein 5.4g (11%) Fat 19.2g (30%) Saturated Fat 7.1g (36%) Polyunsaturated Fat 3.3g (19%) Monounsaturated Fat 7.6g (38%) Trans Fat 0.4g (20%) Cholesterol 52.4mg (17%) Sodium 256.2mg (11%) Potassium 479.5mg (10%) Fiber 5.2g (21%) Sugar 5.4g (11%) Vitamin A 16440.2IU (329%) Vitamin C 2.9mg (3%) Calcium 64.5mg (6%) Iron 1.5mg (8%)

Nutrition Facts

Serving: 12 people

Amount Per Serving

Calories 3241

% Daily Value*

Calories 324.1kcal 16%
Carbohydrates 46.5g 16%
Protein 5.4g 11%
Fat 19.2g 30%
Saturated Fat 7.1g 36%
Polyunsaturated Fat 3.3g 19%
Monounsaturated Fat 7.6g 38%
Trans Fat 0.4g 20%
Cholesterol 52.4mg 17%
Sodium 256.2mg 11%
Potassium 479.5mg 10%
Fiber 5.2g 21%
Sugar 5.4g 11%
Vitamin A 16440.2IU 329%
Vitamin C 2.9mg 3%
Calcium 64.5mg 6%
Iron 1.5mg 8%

* Percent Daily Values are based on a 2,000 calorie diet.