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Rhubarb Dump Cake

Whip up this rhubarb dump cake and make the most out of all that tart summer rhubarb! You’ll only need five ingredients.

This rhubarb dump cake is the embodiment of summer flavors. It’s wonderfully warm and moist with a slightly crispy outer crust.

The tart, soft, and crunchy rhubarb gives the dessert such a refreshing flavor, too.

Warm and Moist Rhubarb Dump Cake with Ice Cream
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Just as any other dump cake, this recipe couldn’t be easier to prepare. And because it tastes best when warm, there’s no need to wait for it to cool!

As it comes out of the oven, go ahead and dig in.

Put on your apron and get ready for your kitchen to smell like heaven! Let’s get baking.

Rhubarb Dump Cake 

Rhubarb dump cake – Is it a cake, a pudding, or a cobbler? I like to think of it as a combination of all three. 

But you know what, it doesn’t really matter. All I know is, it’s delicious.

The balance between sweetness and acidity makes this cake so drool-worthy.

It looks amazing, to boot! I love how the crimson, gooey mixture oozes out of the cream-colored cake. So rustic, am I right?

And the smell? Oh my, one whiff of this cake and you can already tell – there’s no way you’re only eating one slice.

The best part is that it’s such an easy recipe. You won’t even have to stir anything!

Just throw the ingredients in the baking pan and let the oven take care of the rest. 

This recipe can feed a crowd as well, so it’s perfect for your next potluck.

Rhubarb Dump Cake Ingredients: Rhubarb, Granulated Sugar, Strawberry Gelatin Mix, Yellow Cake Mix, Water and Margarine


  • Rhubarb — The star of the cake! You can get pre-sliced rhubarb, but if you’re slicing it yourself, be sure to follow the instructions below.
  • Granulated Sugar — Rhubarb is sour, so sugar helps balance out that tartness.
  • Strawberry Flavored Gelatin Mix — It gives the cake a moist texture. 
  • Yellow Cake Mix — The base of the dessert. Feel free to try other cake mix flavors. 
  • Water — To saturate the dry ingredients, forming a batter.
  • Margarine, Melted — For maximum richness and moistness.

All About Rhubarb

Rhubarb, which is technically a vegetable, not a fruit, has been around for ages.

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It is believed to have originated in Asia and was introduced to Europe in the 14th century.

Because of its tartness and stringy texture, rhubarb is often cooked with sugar, to improve its flavor.

It’s then served with cake or ice cream for a refreshing dessert. 

How to Tell If Rhubarb is Ripe

Just check the length. It should be between 7 to 15 inches long.

Soft and Crumbly Rhubarb Dump Cake

How to Cut Rhubarb 

1. Rinse the rhubarb by running it in cool water. Wipe it dry with paper towels.

2. Cut off the leaves and trim the end of the root. Throw these parts out. They contain a poisonous chemical called oxalic acid, hence, they’re not safe to eat.

3. Cut a small slit at one of the stalk ends. Grab the edge of the slit and peel it down. Repeat the step with the remaining stalks.

4. Cut the stalks into 1-inch slices. 

Pro-tip: cut the fresh rhubarb right before use. Cutting it too soon will cause it to dry out.

Tips for the Best Cake 

  • If you want to use fresh rhubarb, take note of its peak season: field-grown rhubarb grows from late spring to early summer. Hot-house rhubarb is available from January to June.
  • If you don’t have access to fresh rhubarb, though, that’s perfectly fine. This cake is amazing even if you use frozen rhubarb! 

In fact, it doesn’t matter if you use fresh or frozen rhubarb for this recipe.

The rhubarb will soften as it bakes, anyway, so what does it matter if it’s fresh?

Pro-tip: buy pre-sliced frozen rhubarb so you won’t have to worry about slicing anymore.

Thaw frozen rhubarb in the fridge before use. You can also run it through cold water.

  • Rhubarb dump cake freezes well! Cover it with foil and freeze for up to 2 to 3 months.
  • There’s no need to stick to rhubarb. You can use other fruits to make this cake, too, such as strawberries, blackberries, cherries, raspberries, and apples. 
  • Feel free to mix and match. Rhubarb and strawberries, in particular, pair well together.
  • You can also try other cake mix and gelatin flavors as well. I’ve tried it with white cake mix and raspberry Jell-O, and it turned out really well.
  • Add a splash of lemon or some fresh mint for extra flavor. 
  • Be sure to discard the rhubarb’s roots and leaves – these parts aren’t edible. 
Rhubarb Dump Cake Casserole

Why Is It Called Dump Cake? 

If you’re new to baking, this cake recipe is a great place to start.

There’s no need to worry about technical terms such as creaming the butter and sugar or folding the batter. 

You’ll literally dump all the ingredients in the baking pan, hence the name. There are no bowls and any stirring involved. 

It’s one of, if not the easiest types of cake to make. It’s so easy, even kids can do it.

Does Dump Cake Need to Be Refrigerated? 

Yes. Just like most cakes, rhubarb dump cake needs to be refrigerated.

Cover the cake with plastic wrap or place it in an air-tight container, and store it in the fridge for up to 3 to 4 days.

This dessert is best served warm, so reheat it in the microwave right before serving.

Can’t get enough rhubarb? Try these incredible rhubarb dessert recipes!

Rhubarb Dump Cake



Prep time


Cooking time






  • 1 pound rhubarb, sliced into 1/4-inch chunks

  • 1 cup granulated sugar

  • 1 (3-ounce) package strawberry flavored gelatin mix

  • 1 (18.25-ounce) package yellow cake mix

  • 1 cup water

  • 1/4 cup margarine, melted


  • Preheat the oven to 350 degrees Fahrenheit. Grease a 9×13-inch baking dish with butter.
  • Layer the rhubarb slices evenly into the bottom of the dish. Sprinkle the sugar over the rhubarb. Pour in the contents of the gelatin packet, followed by the cake mix, then the water, and melted margarine. There is no stirring needed.
  • Bake for 45 minutes or until the rhubarb slices are tender.
Rhubarb Dump Cake

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author avatar
Kim - InsanelyGood
Hey there! I'm Kim. I love running, cooking, and curling up with a good book! I share recipes for people who LOVE good food, but want to keep things simple :)

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