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Rhubarb Dump Cake

Rhubarb dump cake is an easy no-mix dessert with a golden, buttery cake topping over a sweet-tart rhubarb base. Bake until the top is crisp and browned, with rhubarb bubbling around the edges for that layered, spoonable slice.
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Prep Time 10 minutes
Cook Time 45 minutes
cooling 10 minutes
Total Time 1 hour 5 minutes
Servings: 12 servings
Course: Dessert
Cuisine: American
Calories: 360
Ingredients Equipment Method Notes

Ingredients
  

Rhubarb layer
  • 6 cup fresh rhubarb Dice into bite-size pieces so it cooks evenly.
  • 1.5 cup sugar Sprinkle over rhubarb for a sweet-tart syrupy base.
Cake topping
  • 1 box (15.25 oz) yellow cake mix Use dry cake mix and do not stir.
  • 0.5 cup butter Melt and drizzle over the dry mix.
  • 0.5 cup chopped pecans Optional for extra crunch.
  • Vanilla ice cream For serving; add warm cake straight from the dish.

Equipment

  • 1 sheet pan

Method
 

Prep
  1. Preheat oven to 350°F, then grease a 9x13-inch baking dish.
  2. Spread diced fresh rhubarb evenly in the bottom of the prepared dish and sprinkle with sugar.
Build the dump cake
  1. Pour the yellow cake mix evenly over the rhubarb layer without stirring so it stays dry on top.
  2. Drizzle the melted butter over the cake mix, trying to cover as much of the surface as possible.
  3. Sprinkle with chopped pecans if using, then gently tap the dish to help settle the topping.
Bake and rest
  1. Bake for 40-45 minutes at 350°F until the top is golden brown and the rhubarb is bubbling around the edges.
  2. Let the dump cake cool for 10 minutes before serving warm.
Serve
  1. Spoon servings from the dish and top with vanilla ice cream to melt slightly over the warm cake.

Notes

Pro tip: keep the cake mix dry—no stirring—so you get those crispy, buttery edges on top. Store covered in the refrigerator up to 3 days; reheat individual portions in the microwave until warm. Freezing: freeze baked portions up to 2 months, thaw overnight in the fridge and reheat. Dietary swap: use a butter substitute (or plant-based butter) in the same amount to make the topping dairy-friendly.