Sweet Potato Dump Cake: The Easiest Thanksgiving Dessert
Sweet potato casserole and dump cake had a baby, and it’s everything you want in a holiday dessert. The bottom is rich, custardy sweet potato filling, and the top is a buttery, golden cake crust that practically makes itself.
No mixer, no rolling pins, just layers dumped in a pan. This version uses canned sweet potatoes and a spice-kissed cake mix, so the active work is about 10 minutes. The oven does the rest.
Why This Dump Cake Works
I love a dessert that doesn’t ask much of me. You mix up a sweet potato custard base with just a bowl and a fork, spread it in the pan, then sprinkle a bag of dry cake mix right over the top. Drench it in melted butter, and as it bakes, the butter and cake mix turn into a crackly, crisp topping while the sweet potato layer sets into something like pumpkin pie filling.
The contrast of creamy and crunchy is what keeps me reaching for another spoonful. This recipe has never let me down because you’re not creaming butter or beating eggs to ribbons. Use the right size pan and check it at the 45-minute mark, and you’ll get a dessert that slices cleanly and feeds a crowd without breaking a sweat.
Ingredients
- 1 (29 oz) can sweet potatoes in light syrup, drained: use canned for speed; the syrup adds sweetness and moisture.
- 1 (12 oz) can evaporated milk: whole milk works in a pinch, but evaporated milk gives a richer custard.
- 2 large eggs: they bind the filling.
- 1/2 cup granulated sugar: adjust if your sweet potatoes are already very sweet; I find 1/2 cup is the sweet spot.
- 1 teaspoon pumpkin pie spice: or 1 teaspoon cinnamon plus a pinch of nutmeg.
- 1 (15.25 oz) box yellow cake mix: any brand; a butter or spice cake mix also works well.
- 1/2 cup unsalted butter, melted: salted butter is fine, just omit any additional salt.
- 1/2 cup chopped pecans (optional): for a nutty crunch on top.
Variations / Substitutions
- Spice cake mix: use a box of spice cake mix instead of yellow for extra warmth.
- Pecans on top: scatter 1/2 cup chopped pecans over the butter before baking for a nutty crunch.
- Marshmallow topping: during the last 10 minutes of baking, sprinkle mini marshmallows over the top and bake until puffed and golden.
If you like this, try my Classic Sweet Potato Casserole with Pecan Streusel.
How to Make Sweet Potato Dump Cake
Step 1: Mix the Sweet Potato Base
Preheat your oven to 350°F (175°C) so it’s hot when you’re ready to bake. In a large bowl, mash the drained sweet potatoes with a fork until mostly smooth. A few small lumps are fine. Stir in the 1 (12 oz) can evaporated milk, 2 large eggs, 1/2 cup granulated sugar, and 1 teaspoon pumpkin pie spice until evenly blended.
The mixture will look like a thin pancake batter, pale orange with flecks of spice. Pour it into an ungreased 9×13-inch baking dish and spread it into an even layer.
Step 2: Top with Cake Mix and Butter
Sprinkle the entire box of dry cake mix evenly over the sweet potato base. Don’t stir, don’t press it down, just let it sit in a fluffy layer. Slowly drizzle the 1/2 cup melted butter over the top, trying to cover as much of the dry mix as possible. If you’re using pecans, scatter them on now.
When the butter hits the dry mix, it will start to darken and soak in, creating little rivulets. That’s exactly what you want. Resist the urge to stir; the magic of a dump cake is that the butter and cake mix combine into a crisp topping as it bakes.
Step 3: Bake Until Golden
Slide the dish into the preheated oven and bake for 45 to 50 minutes. The top should be deep golden brown and the edges should bubble thickly. A toothpick inserted near the center should come out with a few moist crumbs clinging to it, not wet batter.
As it bakes, the sweet potato filling will set and the cake topping will puff slightly, then settle into a craggy, crisp surface. The whole kitchen will smell like pumpkin pie and vanilla, which is your signal that it’s almost ready.
Step 4: Cool and Serve
Let the dump cake cool on a wire rack for at least 20 minutes before slicing. This rest allows the filling to firm up so you get clean, neat squares. Serve it warm or at room temperature, with a dollop of whipped cream or a scoop of vanilla ice cream if you like.
The first slice is always the toughest to lift out, but once you get that corner piece, you’ll see the distinct layers: creamy sweet potato on the bottom, a buttery, cinnamon-flecked crust on top. It’s the kind of dessert that looks homemade in the best way, rustic and a little uneven, with crunchy bits and soft pockets all in one bite.
Tips for the Best Dump Cake
- Use canned sweet potatoes packed in syrup, not water, for the smoothest, sweetest base. If you only have fresh, see FAQ.
- Do not stir the cake mix into the filling; let it sit dry so the butter creates a crispy, golden topping as it bakes.
- Check the cake 5 minutes before the baking time ends. Every oven differs, and you want the top deeply golden but not burnt.
- Let the dump cake cool completely if you plan to transport it; it will be much easier to slice and carry.
Storing Leftovers
- Refrigerate: cover tightly and keep in the fridge for up to 4 days.
- Reheating: warm slices in a 350°F oven for 10 minutes to re-crisp the topping.
- Serve cold: it’s also good straight from the fridge, almost like a sweet potato cheesecake square.
Frequently Asked Questions
Can I use fresh sweet potatoes?
Yes. Peel, cube, and boil about 2 pounds of sweet potatoes until tender, then drain well and mash. You’ll need to add an extra 1/4 cup sugar and a splash of milk to mimic the sweetness and moisture of the canned version.
Why didn’t my topping get crispy?
The most common reason is that the butter didn’t saturate enough of the dry cake mix. Make sure you drizzle the melted butter evenly over the top, and don’t stir. Using the full amount of butter is also key.
Can I add marshmallows?
Absolutely. During the last 8 to 10 minutes of baking, sprinkle mini marshmallows over the top and return to the oven until they’re puffed and lightly toasted. Watch closely so they don’t burn.
What other cake mixes work well?
Spice cake mix, butter pecan, or even white cake mix all give great results. Avoid chocolate or dark cakes, which will overpower the sweet potato flavor.
Sweet Potato Dump Cake Recipe
Ingredients
Method
- Preheat oven to 350°F (175°C). In a large bowl, mash drained sweet potatoes until mostly smooth. Stir in evaporated milk, eggs, sugar, and pumpkin pie spice until blended. Pour into an ungreased 9×13-inch baking dish and spread evenly.
- Sprinkle dry cake mix evenly over the top. Do not stir. Drizzle melted butter evenly over cake mix, aiming to cover most of the surface. If using, scatter pecans on top.
- Bake for 45 to 50 minutes, until the top is deep golden brown and the edges are bubbling. A toothpick inserted near the center should come out with moist crumbs.
- Cool on a wire rack for at least 20 minutes before slicing. Serve warm or at room temperature.
