Rhubarb Dump Cake With Crisp Buttery Topping

Rhubarb dump cake has a soft, jammy fruit layer under a crisp, buttery cake-mix topping, and it needs almost no mixing. Chopped rhubarb is tossed into a 9×13-inch dish with sugar, strawberry gelatin and crushed pineapple, then covered with dry cake mix and melted butter. It takes 10 minutes to assemble, bakes for 50 to 60 minutes, and serves 12. Fresh or frozen rhubarb both work.

Ingredients

Fruit Layer

• 5 cups chopped rhubarb
• 1 cup granulated sugar
• 1 package strawberry gelatin mix
• 1 can (20 ounces) crushed pineapple, undrained

Cake Topping

• 1 box yellow or white cake mix
• 3/4 cup unsalted butter, melted

Optional Add-Ins

• 1 cup sliced strawberries for a strawberry rhubarb dump cake
• Vanilla ice cream or whipped cream for serving

Fresh rhubarb should look firm and crisp, with no limp stalks. If you use frozen rhubarb, thaw it and drain the excess liquid first so the filling does not turn watery. The gelatin and pineapple are what make the fruit layer sweet and syrupy, so leave them in rather than trimming the recipe to fewer ingredients.

Layering and Baking the Dump Cake

1. Preheat the oven to 350°F and lightly grease a 9×13-inch baking dish. Spread the chopped rhubarb evenly across the bottom of the pan so every bite gets some tart fruit.
2. Sprinkle the sugar and strawberry gelatin mix over the rhubarb. Pour the crushed pineapple with its juice over the top. The pineapple liquid helps soften the rhubarb while it bakes and creates the syrupy base that makes a dump cake work.
3. If using strawberries, scatter them over the rhubarb mixture for a classic strawberry rhubarb flavor.
4. Sprinkle the dry cake mix evenly over the fruit layer, covering it completely without stirring. Avoid large piles of cake mix, which can leave dry spots after baking.
5. Drizzle the melted butter slowly over the cake mix, covering as much surface area as possible. Pouring in thin rows across the pan helps the topping brown evenly.
6. Bake for 50 to 60 minutes, until the top is golden brown and the fruit is bubbling around the edges. Let the cake cool at least 15 minutes before serving so the filling thickens slightly.

Why Rhubarb Works So Well in a Dump Cake

A dump cake is built on contrast: tart fruit underneath and a buttery crust on top. Rhubarb suits that because it softens quickly while keeping its sharp flavor, and the sugar, gelatin and pineapple balance it. The moisture from the fruit hydrates the dry cake mix as it bakes, which is what gives the cobbler-like texture without any batter.

Fixing a Powdery Top or Watery Filling

• Powdery patches on top: The butter did not reach the cake mix. Drizzle it more evenly, or gently shake the pan before baking so the dry mix settles into a thinner layer. If you see dry spots halfway through baking, drizzle a few extra tablespoons of melted butter over them.
• Watery filling and soggy topping: Usually frozen rhubarb that was not drained. Thaw and drain it first.
• Runny scoops: Serving too soon. The filling thickens as the cake cools, so wait the full 15 minutes.
• Too tart: Add the optional strawberries, which bring sweetness.

Cake Mix, Add-In and Fruit Swaps

• Cake mix flavor: Yellow is classic, and white or butter cake mix also work. Spice cake mix gives a warmer flavor that pairs with tart rhubarb.
• Crunchier topping: Add a small handful of chopped pecans over the cake mix before baking.
• Strawberries: The 1 cup of sliced strawberries turns this into a strawberry rhubarb dump cake. For the same flavor pairing in other forms, try our strawberry rhubarb crisp or strawberry rhubarb pie.

How to Serve Rhubarb Dump Cake

Serve it warm, while the fruit is still bubbling slightly under the crisp topping. Vanilla ice cream or lightly sweetened whipped cream balances the tartness, and small portions with coffee or tea suit the tangy fruit. If you like the dump cake method, the strawberry cheesecake dump cake uses the same approach with a cream cheese layer.

Storing and Reheating Leftovers

• Refrigerator: Cover the dish tightly and refrigerate within 2 hours of serving. It keeps up to 4 days.
• Reheating: Warm individual portions in the microwave, or put the pan in a low oven to help crisp the topping again.

The card lists about 370 kcal per serving for 12 servings, before ice cream or whipped cream.

Rhubarb Dump Cake FAQ

Can I use frozen rhubarb?

Yes. Thaw and drain it first, because extra liquid can make the topping soggy instead of crisp at the edges.

Why is my dump cake still powdery on top?

The melted butter did not fully cover the cake mix. See the fixes above for even coverage and for rescuing dry spots mid-bake.

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