Sweet Potato Casserole Recipe With Streusel and Marshmallows: Crispy Streusel Crown Over Gooey Marshmallow Sky

This sweet potato casserole recipe with streusel and marshmallows delivers the perfect balance of textures—crispy streusel crown, gooey marshmallow clouds, and silky sweet potato filling. The secret lies in layering each component just right, ensuring every bite has a satisfying crunch followed by that melt-in-your-mouth marshmallow magic.

I’ve perfected this recipe over years of holiday gatherings, where it becomes the star of the table.

The foundation starts with a smooth sweet potato base, sweetened just enough to complement the rich flavors without overpowering them. A streusel topping made with flour, butter, and brown sugar adds a buttery crunch that contrasts beautifully with the softness beneath.

The marshmallows, toasted to golden perfection, create a caramelized layer that ties everything together.

By the time it emerges from the oven, you’ll have a casserole that’s visually stunning—golden streusel edges framing a sea of golden-brown marshmallows, all resting on a velvety sweet potato base.

The aroma alone will have everyone gathering around the table, and the first bite will have them asking for seconds. This is the kind of dish that turns a simple side into the centerpiece of any meal.

For extra depth, consider adding a pinch of cinnamon or chopped pecans to the streusel, or a sprinkle of sea salt on the marshmallows before baking. The possibilities are endless, but the core technique remains foolproof—layer, bake, and enjoy the results. Let’s get started on creating this crowd-pleasing classic.

Ingredients for sweet potato casserole recipe with streusel and marshmallows

Six ingredients for the casserole base, five for the streusel crown, and two for the marshmallow magic—simple layers for showstopping results.

The sweet potatoes are non-negotiable—orange-fleshed, firm varieties like Jewel or Beauregard work best. Costco or Trader Joe's usually carry these pre-peeled for convenience, but if you're peeling them yourself, go for 3 pounds total to account for shrinkage. The marshmallows? Kraft or Jet-Puffed are the gold standard here—mini ones toast faster, while jumbo ones create that classic 'cloud' effect. Store your marshmallows in an airtight container with a silica packet to prevent stickiness, and keep them in a cool, dark place for up to 1 year.

No brown sugar for the streusel? White sugar plus 1 tsp molasses works in a pinch, though it won't be quite as rich. Running short on pecans? Toasted walnuts or chopped almonds add a similar crunch. The butter in the streusel should be cold and cubed—this ensures those perfect crunchy clusters. If your flour is old, sift it through a fine-mesh sieve to avoid a dense streusel. For extra depth, I like to add 1/4 tsp nutmeg to the sweet potato filling—it pairs beautifully with the cinnamon in the streusel.

This casserole reheats beautifully—350°F for 20 minutes covered with foil, then uncovered for the last 5 minutes to crisp the streusel. For make-ahead prep, assemble everything a day in advance and refrigerate uncovered (the marshmallows will firm up nicely). Bake straight from the fridge for even browning. Leftovers? 3 days in the fridge or freeze the whole thing for up to 3 months. When reheating from frozen, add 10 minutes to the baking time and cover tightly with foil.

Step-by-step instructions for sweet potato casserole with streusel and marshmallows

Here's how to build that perfect trifecta: velvety sweet potatoes, buttery streusel, and golden marshmallow topping.

Preheat your oven to 375°F and line a baking sheet with parchment paper. Spread the 3 lbs peeled and cubed sweet potatoes in a single layer on the sheet. Roast for 25-30 minutes until fork-tender and caramelized at the edges. I like to toss them halfway through for even browning.

While they bake, let the 2 whole large eggs and 0.5 cup heavy cream come to room temperature. Once the potatoes are done, drain any excess liquid and transfer them to a large mixing bowl. Mash until completely smooth—no lumps should remain. Stir in the room-temperature eggs, 0.5 cup heavy cream, 1.5 cups granulated sugar, 1 tbsp vanilla extract, 1 tsp salt, and 2 tbsp ground cinnamon until fully combined. This mixture should be silky and uniform, ready for the streusel crown.

In a separate bowl, cut the 1 cup unsalted butter into small cubes and let it sit at room temperature for 10 minutes to soften slightly. Add the 1.5 cups all-purpose flour and 0.75 cup packed brown sugar to the bowl. Mix with a fork or your fingers until the mixture resembles coarse crumbs with pea-sized butter pieces throughout.

Fold in the 0.5 cup chopped pecans (if using) and an additional 1 tbsp ground cinnamon for extra warmth. The streusel should hold its shape when pressed but still crumble easily. This texture is what creates that perfect crispy crown when baked. If it feels too dry, add 1-2 teaspoons of cold water to bind it together.

Transfer the sweet potato mixture to a greased 9x13-inch baking dish and spread it evenly. Sprinkle the streusel topping evenly over the sweet potatoes, pressing down gently with your fingers to create a continuous layer. This ensures even baking and maximum crispiness.

Bake at 375°F for 25-30 minutes until the streusel is golden brown and the edges are bubbling. Here's the thing—don't overbake. The streusel should be crisp but not burnt, and the sweet potatoes should still have a slight give when pressed. Remove from the oven and let it cool for 10 minutes before adding the marshmallows.

Spread the 2 lbs large marshmallows evenly over the hot casserole. Use a spoon to help them stick to the streusel layer. Return the casserole to the oven and broil on high for 1-2 minutes, watching closely to prevent burning. The marshmallows should be golden brown and slightly puffed, creating that signature gooey texture.

Immediately sprinkle with 1 tbsp flaky sea salt for a perfect balance of sweet and salty. Let the casserole rest for 5 minutes before serving—this allows the marshmallows to set slightly and makes cutting easier. Serve warm with a scoop of vanilla ice cream or a dollop of whipped cream for the ultimate comfort dessert.

Perfect pairings for this dish

Classic Side Dish

This casserole shines as a holiday centerpiece but works equally well as a Thanksgiving side or Christmas dessert. Its rich, caramelized flavors and perfect textures make it a showstopper that pairs beautifully with roasted turkey or ham.

For a lighter option, serve it alongside grilled chicken or baked fish during summer gatherings. 🍽️

Beverage Pairings

A bold bourbon like Buffalo Trace or wood-fired whiskey complements the sweet potato's depth and the marshmallow's caramel notes. For non-alcoholic options, chilled peppermint tea or vanilla chai balances the richness. Coffee lovers will adore this with a dark roast, especially if sprinkled with cinnamon.

Protein Additions

For a hearty meal, top individual servings with crispy bacon bits or savory sausage crumbles before baking. The salty-sweet contrast elevates the dish. I also love adding toasted pecans to the streusel for extra crunch and richness. For a festive twist, sprinkle dried cranberries over the marshmallows before broiling.

Dessert Pairings

Serve warm slices with vanilla ice cream, whipped cream, or caramel sauce for a decadent finish. A scoop of pistachio gelato adds a nutty contrast to the sweet potato's earthiness. For a lighter option, pair with lemon sorbet to cut through the richness. 🍦

Seasonal Variations

In fall, add pumpkin puree (½ cup) to the sweet potato base for extra depth. For winter, swap marshmallows for toasted coconut flakes and drizzle with honey.

In spring, use mini marshmallows and top with fresh berries for a lighter take. Each season brings a fresh twist while keeping the classic flavors intact.

Frequently asked questions