Rhubarb Dump Cake

Rhubarb Dump Cake is a simple old-fashioned dessert with a tart rhubarb base, sweet yellow cake topping, and buttery golden finish. It comes together quickly with pantry-friendly ingredients and bakes into a soft, bubbly, spoonable dessert that is especially good served warm.

Why You’ll Love It

This dessert is ideal when you want something easy but comforting. The rhubarb cooks down into a juicy, tangy layer while the cake mix and melted butter create a crisp, tender topping. It is a great choice for spring and early summer, and it pairs beautifully with vanilla ice cream.

Ingredients

Rhubarb Layer
• 4 cups fresh rhubarb, diced
• 1 1/2 cups granulated sugar
• 2 tablespoons cornstarch
• 1 teaspoon vanilla extract
• 1/2 cup water
Cake Topping
• 1 package yellow cake mix, 15.25 ounces
• 1/2 cup water
• 1 cup unsalted butter, melted

Instructions

1. Preheat the oven to 350°F (175°C).
2. In a large bowl, combine the diced rhubarb, sugar, cornstarch, vanilla extract, and 1/2 cup of water. Stir until the rhubarb is evenly coated.
3. Pour the rhubarb mixture into a greased 9×13-inch baking dish.
4. Sprinkle the dry yellow cake mix evenly over the rhubarb layer.
5. Drizzle the remaining 1/2 cup water evenly over the cake mix.
6. Pour the melted butter over the top, covering as much of the surface as possible.
7. Bake for 45 to 50 minutes, or until the top is golden brown and the filling is bubbling.
8. Let cool for at least 15 minutes before serving.
Tips for Best Results
Use fresh, firm rhubarb for the best texture and tart flavor. If you want a richer dessert, serve it warm with vanilla ice cream or whipped cream. Make sure the butter is spread as evenly as possible so the topping bakes up golden and not dry in spots. For cleaner serving, let it rest a little longer before scooping.

Storage

Store leftovers covered in the refrigerator for up to 4 days. Reheat individual portions in the microwave or oven before serving. The topping will soften slightly after storage, but the flavor stays excellent.
Rhubarb Dump Cake is one of the easiest ways to turn rhubarb into a cozy homemade dessert. With its sweet cake topping and tart fruit filling, it delivers a comforting balance of flavors with very little effort.

FAQ

Can I use frozen rhubarb?
Yes. Thaw it first and drain excess liquid before using.
Do I have to use yellow cake mix?
Yellow cake mix works best for the classic flavor, but white cake mix can also be used.
Why is my dump cake dry on top?
The butter may not have covered enough of the surface. Try drizzling it more evenly next time.
Can I make it ahead of time?
Yes. It keeps well and can be reheated before serving.
How should I serve it?
It is best served warm, especially with vanilla ice cream or whipped cream.
How long does it last?
Store it in the refrigerator for up to 4 days.