This sweet potato casserole combines smooth, buttery sweet potatoes with brown sugar, cinnamon, crunchy pecans and a layer of toasted marshmallows.
The creamy filling can be prepared ahead, making this an especially convenient side dish for Thanksgiving or Christmas. The marshmallows are added towards the end so they become golden without burning.
Serve this sweet and comforting casserole alongside roast turkey, glazed ham, green beans and homemade dinner rolls.
Why You’ll Love This Sweet Potato Casserole
- Creamy sweet potato filling.
- Golden toasted marshmallow topping.
- Crunchy pecans for texture.
- Suitable for Thanksgiving and Christmas.
- Can be assembled in advance.
- Made with accessible ingredients.
- Easy to customise.
- Feeds a family or holiday gathering.
- Works as a side dish or lightly sweet dessert.
- Attractive addition to a holiday table.
Ingredients You’ll Need
For the Sweet Potato Filling
- 3 pounds sweet potatoes.
- ½ cup unsalted butter, melted.
- ½ cup packed light brown sugar.
- ½ cup whole milk.
- 2 large eggs, lightly beaten.
- 1 teaspoon pure vanilla extract.
- 1 teaspoon ground cinnamon.
- ¼ teaspoon ground nutmeg.
- ½ teaspoon salt.
For the Topping
- 2 cups miniature marshmallows.
- ¾ cup chopped pecans.
- 2 tablespoons melted butter.
- 2 tablespoons packed brown sugar.
- ¼ teaspoon ground cinnamon.
Ingredient Notes
Sweet potatoes: Choose firm, orange-fleshed sweet potatoes with smooth skin. Cut them into equal-sized pieces so they cook evenly.
Butter: Adds richness to the filling and helps the pecan topping become golden.
Brown sugar: Gives the casserole a caramel-like sweetness. The quantity can be reduced if your sweet potatoes are particularly sweet.
Milk: Loosens the mashed sweet potatoes and creates a creamy consistency. Whole milk provides the richest result.
Eggs: Help the filling set while baking. Allow the mashed sweet potatoes to cool slightly before adding them so the eggs do not begin to cook.
Vanilla: Complements the natural sweetness and warm spices.
Pecans: Add crunch and balance the soft filling and marshmallows. Toasting them briefly can intensify their flavour.
Marshmallows: Miniature marshmallows melt and brown more evenly than large ones.
How to Prepare the Sweet Potatoes
Peel the sweet potatoes and cut them into approximately 1-inch pieces.
Keep the pieces similar in size so they become tender at the same time.
Place them in a large saucepan and cover with cold water by approximately one inch. Add a small pinch of salt.
Starting with cold water helps the pieces cook more evenly.
How to Make Sweet Potato Casserole
Step 1: Cook the Sweet Potatoes
Bring the saucepan to a boil over medium-high heat.
Reduce the heat and simmer for approximately 15–20 minutes, or until the sweet potatoes are completely fork-tender.
Drain them thoroughly in a colander.
Return the potatoes to the warm saucepan for one or two minutes to allow excess moisture to evaporate.
Step 2: Mash Until Smooth
Transfer the cooked sweet potatoes to a large mixing bowl.
Mash them with a potato masher until smooth. A few small pieces are acceptable if you prefer a more rustic texture.
Avoid using a blender or food processor excessively, as this can affect the texture.
Step 3: Add the Filling Ingredients
Allow the mashed potatoes to cool for several minutes.
Add:
- Melted butter.
- Brown sugar.
- Milk.
- Lightly beaten eggs.
- Vanilla.
- Cinnamon.
- Nutmeg.
- Salt.
Stir until the ingredients are evenly incorporated and the mixture looks creamy.
Taste the mixture before adding the raw eggs if you want to adjust the sugar or spices safely.
Step 4: Fill the Baking Dish
Preheat the oven to 350°F.
Lightly grease a 9 × 13-inch baking dish.
Spread the sweet potato mixture evenly in the prepared dish and smooth the surface with a spatula.
Step 5: Add the Pecan Topping
Combine the chopped pecans, melted butter, brown sugar and cinnamon in a small bowl.
Sprinkle the mixture over the sweet potato filling.
If you want distinct sections, place the pecans over one half and reserve the other half for marshmallows.
Step 6: Bake the Casserole
Bake uncovered for approximately 20 minutes, until the filling is hot and the pecans are lightly toasted.
Remove the dish carefully from the oven.
Step 7: Add the Marshmallows
Sprinkle the miniature marshmallows evenly over the casserole.
Return it to the oven and bake for another 8–12 minutes, or until the marshmallows are soft and golden.
Watch carefully during the final few minutes because marshmallows can brown quickly.
Step 8: Rest and Serve
Allow the casserole to rest for approximately ten minutes.
The filling will continue to set slightly as it cools.
Serve warm.
Tips for the Best Sweet Potato Casserole
Drain the Potatoes Thoroughly
Excess water can make the filling thin. Return the drained potatoes to the warm pan briefly to release additional steam.
Do Not Add Eggs to Very Hot Potatoes
Allow the mashed potatoes to cool slightly before adding the eggs.
Taste Before Adding the Eggs
Adjust the sugar, salt and spices before raw eggs are incorporated.
Use Miniature Marshmallows
Small marshmallows create a more even topping and are easier to portion.
Add Marshmallows Near the End
If added at the beginning, the marshmallows may melt completely or burn before the filling is ready.
Watch the Casserole Closely
Marshmallows can change from lightly golden to burnt very quickly.
Allow It to Rest
Resting for ten minutes helps the filling firm up and makes serving easier.
Sweet Potato Casserole Variations
Sweet Potato Casserole Without Marshmallows
Leave out the marshmallows and cover the entire surface with the pecan mixture.
Casserole Without Pecans
Omit the nuts and use only marshmallows. This is suitable for guests with nut allergies, provided every ingredient and preparation surface is safe.
Brown Sugar Pecan Topping
Combine:
- ¾ cup chopped pecans.
- ½ cup brown sugar.
- ⅓ cup all-purpose flour.
- ¼ cup melted butter.
Sprinkle this streusel-style mixture over the filling before baking.
Maple Sweet Potato Casserole
Replace part of the brown sugar with pure maple syrup. Reduce the milk slightly if the mixture becomes too loose.
Bourbon Sweet Potato Casserole
Add a small amount of bourbon to the filling for an adult holiday variation. Test the quantity before publishing a precise version.
Orange Sweet Potato Casserole
Add finely grated orange zest to the filling for a brighter flavour.
Spiced Sweet Potato Casserole
Add a small amount of ground ginger, cloves or allspice.
Dairy-Free Sweet Potato Casserole
Use plant-based butter and unsweetened non-dairy milk. Check that the marshmallows meet your dietary requirements.
Boiling Versus Roasting Sweet Potatoes
Boiling
Boiling is faster and produces soft potatoes that are easy to mash. They must be drained thoroughly to prevent a watery casserole.
Roasting
Roasting concentrates the natural sweetness and reduces excess moisture.
To roast them, bake whole sweet potatoes at approximately 400°F until completely soft. Allow them to cool, remove the skins and scoop out the flesh.
Both methods work, but the flavour and moisture level may differ.
What to Serve With Sweet Potato Casserole
Serve it with:
- Roast turkey.
- Baked ham.
- Roast chicken.
- Pork tenderloin.
- Roast beef.
- Creamy mashed potatoes.
- Roasted green beans.
- Honey glazed carrots.
- Garlic Parmesan Brussels sprouts.
- Homemade dinner rolls.
- Mac and cheese.
- Stuffing or dressing.
- Cranberry sauce.
For a complete holiday menu, pair it with Easy Roasted Green Beans, Creamy Mashed Potatoes, Honey Glazed Carrots and Homemade Dinner Rolls.
Can You Make Sweet Potato Casserole Ahead?
Yes. Prepare the sweet potato filling and spread it in the greased baking dish.
Allow it to cool, cover tightly and refrigerate for up to two days.
Prepare the pecan mixture separately and store it in an airtight container. Add the pecans before baking and add the marshmallows during the final minutes.
A chilled casserole may require additional baking time. Bake until the centre is thoroughly hot before adding the marshmallows.
How to Store Leftovers
Allow the casserole to cool.
Cover the baking dish or transfer the leftovers to an airtight container.
Refrigerate within two hours and use within 3–4 days.
The marshmallow topping will become softer during storage.
Can You Freeze Sweet Potato Casserole?
Yes, but freeze it without the marshmallow topping for the best result.
Prepare the filling and place it in a freezer-safe baking dish. Cool completely, wrap securely and freeze for up to two months.
Thaw overnight in the refrigerator.
Add the pecan mixture before reheating and the marshmallows near the end.
How to Reheat Sweet Potato Casserole
In the Oven
Cover the casserole loosely with aluminium foil and reheat at 350°F until thoroughly hot.
Remove the foil during the final few minutes if you want to refresh the topping.
In the Microwave
Heat individual portions in short intervals until hot.
The microwave is convenient, but the topping will be softer.
Frequently Asked Questions
Are yams and sweet potatoes the same?
In many American supermarkets, orange-fleshed sweet potatoes are labelled as yams. True yams are a different root vegetable.
Can I use canned sweet potatoes?
Yes, but drain them thoroughly and check whether they contain added syrup. Reduce the sugar if necessary.
Why is my sweet potato casserole watery?
The potatoes may not have been drained completely, or too much liquid may have been added. Allow boiled potatoes to release steam before mashing.
Can I leave out the eggs?
The eggs help the filling set. They can be omitted, but the finished casserole will be softer and may require adjustments to the milk.
How do I stop the marshmallows from burning?
Add them only during the final 8–12 minutes and watch the casserole continuously near the end.
Can I use large marshmallows?
Yes. Cut them into smaller pieces or arrange them evenly so the topping melts consistently.
Is sweet potato casserole a side dish or dessert?
It is traditionally served as a holiday side dish in the United States, although its sweetness also makes it similar to a dessert.
Can I prepare it the night before Thanksgiving?
Yes. Assemble and refrigerate the sweet potato filling, then add the toppings while baking the following day.
Sweet Potato Casserole Recipe Card
Preparation time: 25 minutes
Cooking time: 35–40 minutes
Total time: Approximately 1 hour
Servings: 10
Course: Side Dish
Cuisine: American
Method: Baking
Ingredients
Sweet Potato Filling
- 3 pounds sweet potatoes.
- ½ cup unsalted butter, melted.
- ½ cup packed light brown sugar.
- ½ cup whole milk.
- 2 large eggs, lightly beaten.
- 1 teaspoon vanilla extract.
- 1 teaspoon ground cinnamon.
- ¼ teaspoon ground nutmeg.
- ½ teaspoon salt.
Topping
- 2 cups miniature marshmallows.
- ¾ cup chopped pecans.
- 2 tablespoons melted butter.
- 2 tablespoons brown sugar.
- ¼ teaspoon cinnamon.
Instructions
- Peel and cut the sweet potatoes into equal-sized pieces.
- Place them in a large saucepan and cover with cold water.
- Boil, then simmer for 15–20 minutes until fork-tender.
- Drain thoroughly and return them briefly to the warm pan.
- Mash until smooth.
- Allow the potatoes to cool slightly.
- Mix in the butter, brown sugar, milk, eggs, vanilla, cinnamon, nutmeg and salt.
- Preheat the oven to 350°F.
- Grease a 9 × 13-inch baking dish.
- Spread the filling evenly inside.
- Combine the pecans, butter, brown sugar and cinnamon.
- Sprinkle the pecan mixture over the filling.
- Bake for 20 minutes.
- Add the miniature marshmallows.
- Bake for another 8–12 minutes, until golden.
- Rest for ten minutes before serving.