5 Ingredient Rhubarb Dump Cake Will Blow Your Mind Deliciously

You know those desserts that taste like you spent all day in the kitchen but secretly took you 10 minutes? That’s my rhubarb dump cake—the ultimate “cheat” dessert that never fails to impress. Every summer when my grandma’s rhubarb patch would go wild, we’d make this exact recipe together. I’d stand on a step stool, watching her toss ingredients into the pan with that magical “just dump it in” attitude. Now, decades later, it’s still my go-to when I need something sweet, tangy, and ridiculously easy. The best part? That golden, buttery top hiding the tender rhubarb underneath—pure nostalgia in every bite.

Why You’ll Love This Rhubarb Dump Cake

This rhubarb dump cake is the kind of dessert that makes you look like a kitchen hero with zero effort. It’s the ultimate “set it and forget it” treat—perfect for when you’re short on time but still want that homemade magic. Trust me, once you try it, you’ll be hooked.

Perfect for Busy Bakers

No fancy skills required here! You literally dump everything in the pan—no mixing bowls, no whisking, no stress. It’s foolproof, which is why I make it when I’m too tired to even think about baking but still crave something warm and comforting.

Sweet-Tangy Flavor Balance

The rhubarb’s natural tartness plays beautifully against the sugar and buttery cake mix. It’s like a little flavor fireworks show in your mouth—bright, sweet, and just the right amount of zing. Even people who swear they don’t like rhubarb end up sneaking seconds.

Rhubarb Dump Cake Ingredients

Grab these simple ingredients—chances are you already have most in your pantry! The magic happens when they all come together in that baking dish.

• 4 cups chopped rhubarb – fresh or frozen (no need to thaw!)
• 1 cup sugar – adjust up to 1 1/4 cups if your rhubarb is extra tart
• 1 box (15.25 oz) yellow cake mix – the generic kind works perfectly
• 1 cup water – cold tap water is fine
• 1/2 cup butter, melted – I use salted for that extra flavor punch

That’s it! No eggs, no fancy extracts—just five humble ingredients that transform into something magical.

How to Make Rhubarb Dump Cake

Okay, ready for the easiest dessert you’ll ever make? Let’s walk through this step by step—it’s so simple, you’ll have it memorized after one try. Just remember: no mixing allowed! That’s the beauty of a dump cake.

Step 1: Prep the Rhubarb Layer

First, preheat that oven to 350°F (175°C)—trust me, you want it nice and hot before the pan goes in. Grab your 9×13-inch baking dish and give it a quick grease with butter or non-stick spray. Now toss in those 4 cups of chopped rhubarb and spread them out evenly—I like to use my hands to make sure there are no big clumps. Think of it like tucking the rhubarb into a cozy bed!

Step 2: Add Sugar and Cake Mix

Here’s where the magic starts! Sprinkle that cup of sugar evenly over the rhubarb—no need to stir (I know it’s tempting!). Then, open your cake mix and just…dump it right on top. Use your fingers to gently pat it down so it covers everything, but again—no mixing! We want those distinct layers to work their magic in the oven.

Step 3: Drizzle and Bake

Now for the good stuff: take your melted butter and pour it as evenly as you can over the cake mix. Then do the same with the water—I like to zigzag mine across the pan. Pop it in the oven for 45-50 minutes until you see that gorgeous golden-brown crust form. The smell? Absolutely heavenly. When those edges are bubbling and the top looks crisp, you’ll know your rhubarb dump cake is ready to rock!

Tips for the Best Rhubarb Dump Cake

Here’s my secret weapon for perfect results every time: taste your rhubarb before adding sugar! If it makes you pucker, bump up the sugar to 1 1/4 cups. Frozen rhubarb works great—just toss it in frozen to prevent extra liquid. And don’t skimp on the butter drizzle—I use the back of a spoon to spread any dry cake mix spots. Pro tip: let it rest 10 minutes before serving so the juices thicken up just right.

Rhubarb Dump Cake Variations

Once you’ve mastered the basic rhubarb dump cake, try these fun twists! My favorite? Swap half the rhubarb for strawberries—that classic combo makes the flavors sing. Craving crunch? Add 1/2 cup oats to the cake mix layer before baking. For a fancy touch, sprinkle sliced almonds on top with the butter. The beauty of dump cakes? You can play around without messing up that perfect simplicity.

Serving and Storing Rhubarb Dump Cake

Oh, you have to serve this warm with a big scoop of vanilla ice cream—the way the cold cream melts into those sweet-tart rhubarb pockets is pure magic! Leftovers? Just cover the pan with foil or transfer slices to an airtight container. It keeps beautifully at room temp for 2 days (if it lasts that long!). For longer storage, pop it in the fridge—though I always reheat slices for that just-baked goodness.

Rhubarb Dump Cake Nutritional Information

Here’s the scoop on nutrition—but remember, these are rough estimates since ingredients vary! One slice (about 1/12th of the pan) clocks in around 280 calories. The sugar content comes mostly from the rhubarb’s natural tartness needing balance, and that buttery topping? Worth every delicious gram.

Common Questions About Rhubarb Dump Cake

I get asked these questions all the time—so let’s tackle the big ones! Whether you’re a dump cake newbie or just need a quick refresher, here’s everything you need to know.

Can I Use Frozen Rhubarb?

Absolutely! In fact, I keep bags of chopped frozen rhubarb in my freezer just for this recipe. Here’s the trick: use it straight from frozen—no thawing needed. The extra ice crystals actually help create those delicious juices. Just measure it while still frozen (pack it gently into your measuring cup) and proceed exactly as written. Easy peasy!

How Do I Know When It’s Done?

Look for three signs: 1) The whole top should be golden brown—no pale yellow spots of dry cake mix left. 2) The edges will be bubbling like a little rhubarb volcano. 3) When you gently jiggle the pan, the center shouldn’t slosh (though it’ll still be slightly wobbly). If in doubt, give it another 5 minutes—dump cakes are very forgiving!

Can I Make This Ahead?

You bet! Assemble everything in the pan (right up to adding the butter and water), then cover tightly with foil and refrigerate overnight. When ready to bake, just pop it straight into a cold oven, then set to 350°F—the gradual heating prevents sogginess. Add 5-10 extra minutes to the bake time since it’s starting cold. Perfect for hassle-free entertaining!

Print