Sweet Potato Casserole with Marshmallows and Pecan Topping
This sweet potato casserole combines creamy mashed sweet potatoes with warm cinnamon, a crunchy brown sugar pecan topping, and toasted marshmallows for a classic holiday side dish that can be prepared ahead.
Prep
25 min
Cook
1 hr 5 min
Total
1 hr 30 min
Servings
10 servings (one 9×13-inch casserole)
Ingredients
Tools that make this easier
Optional — the recipe works without them.
As an Amazon Associate, I earn from qualifying purchases.
Instructions
- 1
Place the sweet potato cubes in a large pot and cover with water. Bring to a boil over high heat, then reduce to medium and simmer for 15–20 minutes until the cubes are easily pierced with a fork. It's ready when a fork slides into the largest sweet potato cubes without resistance.
- 2
Drain the sweet potatoes thoroughly and return them to the warm pot. Let them steam for 2–3 minutes over low heat, stirring gently, to evaporate excess moisture. It's ready when the bottom of the pot looks dry and no water collects around the potatoes.
- 3
Heat the oven to 350°F and lightly grease a 9×13-inch baking dish with a little of the softened butter (about 3 minutes).
- 4
Mash the drained sweet potatoes in a large mixing bowl until mostly smooth. Add the remaining softened butter, brown sugar, milk, beaten eggs, vanilla extract, cinnamon, and salt, then mix until evenly combined (about 7 minutes). It's ready when the mixture is creamy and evenly colored, with no large potato lumps or streaks of egg.
- 5
Transfer the sweet potato mixture to the prepared baking dish and spread it into an even layer. Bake uncovered at 350°F for 25 minutes. It's ready when the surface looks set rather than liquid and the edges begin to puff slightly.
- 6
While the casserole bakes, combine the flour, melted butter, and 1/2 cup of the chopped pecans in a medium bowl. Stir until the flour is moistened and the mixture forms coarse crumbs (about 4 minutes). It's ready when the topping forms loose, crumbly clusters instead of dry flour or a smooth paste.
- 7
Remove the casserole from the oven and scatter the pecan mixture evenly over the surface. Return it to the oven and bake for another 10 minutes at 350°F. It's ready when the pecan topping looks lightly toasted and the edges of the casserole are bubbling gently.
- 8
Scatter the mini marshmallows evenly over the pecan topping and bake for another 5–8 minutes at 350°F. Sprinkle with the reserved pecans before serving. It's ready when the marshmallows are puffed and lightly golden, with no dark or burnt patches.
- 9
Let the casserole rest for 5 minutes before serving so the filling can settle and the topping is easier to portion. It's ready when the edges have settled and each portion can be scooped without the filling running.
Used in this recipe: 9×13 Baking Dish (Amazon, affiliate links)
Notes
Tips for Success
- Drain the sweet potatoes thoroughly and let them steam briefly before mashing. Excess moisture makes the filling loose and prevents the pecan topping from staying crisp, while adding the marshmallows near the end keeps them soft and toasted instead of overbrowned.
- After boiling, drain the sweet potatoes well and steam them briefly in the warm pot before mashing. Bake the filling before adding the pecan topping, then add the marshmallows only for the final 5–8 minutes. If the marshmallows brown too quickly, loosely cover the dish with foil; if the topping needs more color, watch it closely during the final minutes.
Common Mistakes to Avoid
- The casserole turns watery or the pecan and marshmallow topping becomes soggy or scorched. Wet sweet potatoes release moisture during baking, while marshmallows added too early can darken before the filling is ready.
Nutrition (per serving)
360 kcal
Calories
6g
Protein
57g
Carbs
13g
Fat
6g
Fiber
290mg
Sodium
This sweet potato casserole combines a creamy, cinnamon-spiced filling with a buttery pecan crumble and toasted marshmallows for a classic holiday side. The filling bakes first, giving the pecan topping time to turn crisp before the marshmallows go on for the final minutes. With a make-ahead option and clear steps for keeping the filling from turning watery, this sweet potato casserole is practical to prepare for a holiday meal.
Ingredients
- Sweet potatoes: 4 lb, peeled and cut into 1-inch cubes.
- Unsalted butter: 6 tbsp, divided, with 4 tablespoons softened and 2 tablespoons melted.
- Brown sugar: 1/3 cup, packed.
- Milk: 1/3 cup, at room temperature.
- Eggs: 2, lightly beaten.
- Vanilla extract: 1 tsp.
- Ground cinnamon: 1 tsp.
- Salt: 1/2 tsp.
- All-purpose flour: 1/3 cup.
- Chopped pecans: 3/4 cup, divided, with 1 tablespoon reserved for garnish.
- Mini marshmallows: 2 cups. The room-temperature milk helps the filling mix evenly, while softened butter blends into the potatoes without leaving lumps. Keep the melted butter separate for the pecan crumble.
How To Make It
- Boil the sweet potatoes. Place the cubes in a large pot, cover with water, and bring to a boil over high heat. Reduce the heat to medium and simmer for 15–20 minutes. The largest cubes should be easy to pierce with a fork, without resistance.
- Drain and dry the potatoes. Drain thoroughly, return the potatoes to the warm pot, and let them steam over low heat for 2–3 minutes, stirring gently. The bottom of the pot should look dry, with no water collecting around the potatoes.
- Prepare the baking dish. Heat the oven to 350°F. Lightly grease a 9×13-inch baking dish with some of the softened butter.
- Mix the filling. Mash the sweet potatoes in a large mixing bowl until mostly smooth. Add the remaining softened butter, brown sugar, milk, beaten eggs, vanilla, cinnamon, and salt. Mix until creamy and evenly colored, with no large potato lumps or streaks of egg.
- Bake the filling. Spread the mixture in the prepared baking dish and bake uncovered at 350°F for 25 minutes. The surface should look set rather than liquid, and the edges should begin to puff slightly.
- Make the pecan topping. While the filling bakes, combine the flour, melted butter, and 1/2 cup of the chopped pecans in a medium bowl. Stir until the flour is moistened and loose, coarse crumbs form. The mixture should form loose, crumbly clusters rather than dry flour or a smooth paste.
- Add the pecan crumble. Scatter the mixture evenly over the casserole and return it to the oven for another 10 minutes at 350°F. Look for lightly toasted pecans and gentle bubbling around the edges.
- Finish with marshmallows. Spread the mini marshmallows evenly over the pecan layer. Bake for another 5–8 minutes at 350°F, until the marshmallows are puffed and lightly golden, with no dark or burnt patches. Sprinkle with the reserved pecans.
- Rest before serving. Let the casserole rest for 5 minutes so the filling can settle. The edges should look settled, and each portion should scoop cleanly without the filling running.
Why Drying the Sweet Potatoes Matters
Sweet potatoes can retain water after boiling, and excess moisture can loosen the filling as it heats. That extra liquid can also soften the pecan crumble instead of letting it stay crisp. Briefly steaming the drained potatoes in the warm pot allows moisture to escape before the butter, milk, and eggs go in. This gives the filling a thicker, more cohesive texture that supports the two toppings. The order of the toppings matters, too. Baking the filling first gives it time to set, while the pecan crumble gets a separate stretch in the oven to toast. Adding the marshmallows near the end keeps them soft and golden rather than overbrowned.
How to Fix a Watery Filling or Burnt Topping
If the filling seems watery: The potatoes may have retained too much moisture after boiling. Drain them thoroughly and steam them briefly before mashing. If the casserole is already baking, give the filling time to set before adding the toppings rather than covering it with marshmallows too early. If the pecan topping turns soggy: Excess moisture from the filling can soften the crumble. Drying the potatoes well and baking the filling before adding the pecans helps preserve the contrast between the creamy base and crunchy topping. If the marshmallows brown too quickly: Loosely cover the dish with foil to shield the surface from direct heat. If the topping needs more color, watch it closely during the final minutes so the marshmallows do not scorch.
Substitutions
These are untested alternatives, so expect some differences in flavor or texture.
- Milk: Evaporated milk can replace regular milk for a richer filling with a more concentrated dairy flavor.
- Chopped pecans: Chopped walnuts can provide a similar crunch, with a more earthy and slightly bitter taste.
- Mini marshmallows: Large marshmallows cut into quarters create bigger, stickier toasted patches and may need closer attention while baking.
- Brown sugar: Maple syrup adds a woodsy flavor and extra moisture, making the filling slightly softer.
Make-Ahead Tips
The sweet potato filling can be prepared and spread in the greased baking dish up to 24 hours ahead. Cover and refrigerate it, and keep the pecan topping in a separate airtight container at room temperature. When you’re ready to bake, let the chilled dish sit at room temperature for about 20 minutes while the oven heats. Add the pecan topping and bake at 350°F until the center is hot, allowing approximately 10–15 extra minutes because the filling starts cold. Add the marshmallows for the final 5–8 minutes. The filling’s storage time starts when it is prepared, not when it goes into the oven.
How to Store and Reheat Sweet Potato Casserole
Refrigerate leftovers within 2 hours of baking in a shallow, airtight container. They will keep for 3–4 days, although the marshmallow topping may soften during storage. For individual portions, microwave until heated through. To reheat the whole casserole, cover it and warm it in a 325°F oven until the center reaches 165°F. For longer storage, freeze the cooled casserole without the marshmallow topping in a freezer-safe container for up to 2 months. Thaw overnight in the refrigerator, reheat to 165°F, and add fresh marshmallows during the final minutes of reheating.
What to Serve With Sweet Potato Casserole
The sweet filling and crunchy topping pair well with savory main dishes and vegetable sides. Try serving it alongside:
- Roast turkey and gravy for a traditional holiday meal.
- Herb-roasted chicken for a cozy Sunday dinner.
- Green bean casserole for a classic combination of creamy and crisp side dishes.
- Roasted Brussels sprouts for a savory, slightly bitter contrast to the sweet potatoes and marshmallows.
FAQ
Can sweet potato casserole be made ahead of time?
Yes. Prepare the filling up to 24 hours ahead, cover it, and refrigerate it. Store the pecan topping separately at room temperature, then add it before baking and finish with marshmallows near the end.
Can you make sweet potato casserole with marshmallows and pecan topping?
Yes. This version uses a buttery pecan crumble for crunch and mini marshmallows for a soft, toasted finish. Adding each topping at a different stage helps preserve their distinct textures.
How do you store and reheat sweet potato casserole?
Refrigerate leftovers in a shallow, airtight container within 2 hours of baking and use them within 3–4 days. Reheat individual portions in the microwave or warm the covered casserole in the oven until its center reaches 165°F.
