Sweet Potatoes with Marshmallows

This sweet potato casserole with marshmallows combines creamy spiced sweet potatoes with a crunchy pecan streusel and gooey marshmallow topping. It's the dish that disappears first at every holiday gathering, bringing together the perfect balance of sweet, savory, and nostalgic flavors in every bite.

I first made this casserole when hosting Thanksgiving as a newlywed, nervously following my mother in law's cherished recipe. Despite my cooking anxiety, it turned out perfectly, earning me an official welcome into family holiday cooking traditions.

Ingredients

• Sweet potatoes the star ingredient that provides natural sweetness and velvety texture when mashed. Look for firm potatoes with no soft spots for best results
• Butter adds richness to both the potato mixture and streusel topping. Use unsalted to control the salt level
• Brown sugar provides a deep molasses flavor that complements the natural sweetness of the potatoes
• Maple syrup adds complexity beyond just sweetness. Use pure maple syrup rather than pancake syrup
• Cinnamon brings warm spice notes that enhance the sweet potato flavor
• Vanilla extract rounds out the flavor profile with aromatic sweetness
• Pecans create essential textural contrast. Toast them lightly before chopping for enhanced flavor
• Mini marshmallows create that nostalgic golden brown topping. The mini size melts more evenly than large ones
• Flour helps bind the streusel topping ingredients together
• Egg provides structure to the sweet potato mixture

Step-by-Step Instructions

Roast The Sweet Potatoes

Preheat your oven to 350°F and prepare a foil lined baking sheet with cooking spray. Pierce each sweet potato several times with a fork to vent steam during baking. Roast for 45 minutes to an hour until completely tender when pierced with a knife. The slow roasting intensifies the natural sugars and creates a deeper flavor than boiling.

Create The Sweet Potato Filling

Once potatoes are cool enough to handle, split them open and scoop the flesh into a large mixing bowl. Add melted butter, milk, brown sugar, maple syrup, cinnamon, egg, and vanilla. Use a potato masher or hand mixer to combine everything until mostly smooth with just a few small lumps for texture. The mixture should be fluffy but still have some body.

Prepare The Base Layer

Grease your baking dish thoroughly with cooking spray, ensuring all corners are coated. Spread the sweet potato mixture evenly in the dish, using the back of a spoon to create a smooth surface. A 9 inch square pan or 2 quart baking dish works perfectly for this recipe.

Make The Streusel Topping

In a separate bowl, combine brown sugar, flour, melted butter, and chopped pecans. Mix with a fork until the mixture resembles coarse crumbs with visible pecan pieces throughout. This topping provides the essential textural contrast to the soft sweet potatoes.

First Bake

Sprinkle the streusel mixture evenly over the sweet potatoes, covering the entire surface. Bake at 350°F for 25 to 30 minutes until the topping begins to turn golden brown and the casserole is heated through.

Add The Marshmallow Magic

Remove the casserole from the oven and quickly sprinkle mini marshmallows evenly across the top. Return to the oven for just 3 to 5 minutes until the marshmallows puff up and turn golden brown. Watch carefully during this final bake as marshmallows can go from perfect to burnt very quickly.

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My grandmother always insisted on using real maple syrup in this recipe, never the imitation kind. She would say that sweet potatoes deserve respect, and cutting corners on the maple syrup was disrespectful to the dish. That lesson has stayed with me through decades of cooking, especially during the holidays when food carries so much meaning.

Make Ahead Instructions

This casserole is perfect for busy holiday meals because most of the work can be done in advance. Prepare the sweet potato mixture and transfer it to your baking dish, then cover tightly with plastic wrap and refrigerate for up to two days. The streusel topping can also be made ahead and stored separately in an airtight container in the refrigerator. When ready to bake, remove the casserole from the refrigerator and let it sit at room temperature for about 30 minutes. Add the streusel topping and bake as directed, adding a few extra minutes to the baking time if the casserole is still cold. Add the marshmallows during the final minutes of baking as directed.

Flavor Variations

While this classic version has stood the test of time, there are several delicious variations you might enjoy. For a spiced version, add 1/4 teaspoon each of nutmeg and ginger along with the cinnamon. For a citrusy twist, add the zest of one orange to the sweet potato mixture. You can also experiment with the topping by substituting walnuts for pecans or adding a tablespoon of bourbon to the sweet potato mixture for a sophisticated adult version. Some families prefer their sweet potato casserole less sweet, in which case you can reduce the brown sugar to 2 tablespoons in the potato mixture.

Serving Suggestions

This sweet potato casserole pairs beautifully with roasted turkey, glazed ham, or prime rib for holiday meals. The sweetness complements savory main dishes and gravy particularly well. For a complete holiday spread, serve alongside green bean casserole, cranberry sauce, and dinner rolls. Some people even enjoy leftovers for breakfast the next day, warmed up with a dollop of Greek yogurt on top. If serving for a potluck, transport the casserole without the marshmallows and add them just before the final bake at your destination.

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Commonly Asked Questions

→ Can I make sweet potato casserole ahead of time?

Yes! You can prepare the sweet potato mixture and add the streusel topping up to 2 days in advance. Cover tightly and refrigerate. When ready to serve, bring to room temperature, then bake as directed. Add the marshmallows during the final few minutes of baking for best results.

→ Can I use canned sweet potatoes instead of fresh?

Absolutely! Drain and rinse 2 cans (about 15-16oz each) of sweet potatoes. You'll skip the initial roasting step and proceed directly to mashing them with the other ingredients. The flavor may be slightly different, but it's a great time-saving option.

→ What's the best way to prevent marshmallows from burning?

Add the marshmallows only during the last 3-5 minutes of baking time. Watch them closely as they melt quickly and can go from perfectly golden to burnt in a matter of minutes. You can also position the rack in the middle of the oven rather than too close to the heating element.

→ Can I make this casserole without marshmallows?

Certainly! The pecan streusel topping provides plenty of flavor and texture on its own. You can simply omit the marshmallows, or double the streusel topping for extra crunch. The sweet potato base has enough flavor to stand alone with just the streusel.

→ Is there a way to make this dish healthier?

Yes, you can reduce the sugar by cutting the brown sugar amount in half in both the filling and topping. Use milk alternatives like almond or oat milk, and reduce the butter by half. For a less sweet version, skip the marshmallows entirely and just use the pecan topping, perhaps adding extra nuts for protein and healthy fats.

→ How do I know when my sweet potatoes are fully cooked?

Sweet potatoes are done when you can easily pierce them with a fork all the way to the center with little resistance. When roasting whole, this typically takes 45-60 minutes at 350°F, depending on the size of your potatoes. They should feel soft when gently squeezed (using an oven mitt).