Easy Strawberry Rhubarb Cake (The Best Dump Cake Recipe)

The Sweet-Tart Cake That Practically Makes Itself

If you have ever stood in the kitchen with a pile of fresh rhubarb and a pint of strawberries and had no idea what to make, this is your answer. This Easy Strawberry Rhubarb Cake is the kind of recipe that feels almost too simple, yet the result is so golden, so bubbly, and so irresistibly good that people will genuinely ask if you made it from scratch. Technically, you kind of did.

This is a classic strawberry rhubarb dump cake in the best possible way. You layer the sweet-tart fruit on the bottom, shower it with dry cake mix, dot it with cold butter, and let the oven work its magic. What comes out is somewhere between a cobbler and a crumble, with jammy fruit bubbling up through a buttery, crisp-edged topping. It is the ultimate easy dessert recipe for spring and summer, and it doubles beautifully as a strawberry rhubarb breakfast cake with your morning coffee.

Why This Strawberry Rhubarb Dump Cake Works So Well

The secret is balance. Rhubarb is aggressively tart on its own, but when it meets ripe strawberries and a generous scoop of sugar, something magical happens. The lemon zest brightens everything up, and the cornstarch thickens the juices into a glossy, spoonable filling. On top, the dry cake mix absorbs all those fruit juices as it bakes, creating a texture that is crispy on the edges and tender in the center.

A few things genuinely matter here:

• Cold butter, not melted. Thin slices of cold butter melt slowly and evenly over the cake mix as it bakes, which is what creates that gorgeous crumbly, golden crust. Melted butter makes the topping dense and greasy.
• Fresh rhubarb if you can get it. Frozen rhubarb works, but fresh gives you better texture and a brighter flavor.
• Do not stir the layers. This is a dump cake. Trust the process.

Using a good quality box of cake mix and real butter makes a noticeable difference in the final result. The right baking dish matters too, as a 9x13 gives you the ideal fruit-to-topping ratio.

How To Make Strawberry Rhubarb Cake With Cake Mix

The steps here are genuinely simple, which is exactly the point. Chop your rhubarb into half-inch pieces and slice your strawberries, then toss them with sugar, cornstarch, vanilla, and lemon zest in a bowl. This short rest lets the fruit start releasing its juices, which become the sauce.

Spread the fruit into your baking dish, then sprinkle the dry cake mix directly over the top in an even layer. Do not mix it in, and do not add water. The juice from the fruit will hydrate the cake mix from below as everything bakes together.

Finally, cover the surface with thin slices of cold butter. The more coverage the better, but do not stress if there are small gaps.

Chef's Tip: If you notice dry spots of cake mix on top after baking, it means a few areas did not get enough butter coverage. Next time, slice the butter even thinner, or grate it frozen over the top for perfect distribution.

Bake at 350 degrees F for 45 to 55 minutes. You are looking for a deep golden top and fruit that is actively bubbling around the edges. Let it rest for at least 15 minutes before digging in so the filling has time to set up.

Serving This Strawberry Rhubarb Cobbler With Cake Mix

This cake is wonderful served warm, straight from the dish, with a generous scoop of vanilla ice cream melting into the crevices. Whipped cream is equally perfect. For a strawberry rhubarb breakfast cake situation, serve it at room temperature the next morning with a drizzle of cream or a spoonful of Greek yogurt.

It is the kind of dessert that travels well to potlucks, tastes even better the next day, and disappears fast every single time.

Ready to make it? Here is the full step-by-step recipe:

Easy Strawberry Rhubarb Cake (The Best Dump Cake Recipe)

This easy Strawberry Rhubarb Cake comes together in minutes with simple ingredients and a buttery cake mix topping. The perfect sweet-tart dessert for spring and summer gatherings.

Prep:10 mins

Cook:50 mins

Total:60 mins

Yield:9 servings

Cuisine:American

Yield: 9 servingsCalories: 380Protein: 4g

Carbs: 58gFat: 15gSat. Fat: 9gFiber: 2gSugar: 34gSodium: 340mg

Ingredients

Units

USM

Scale

1x2x3x

• 3 cups fresh rhubarb, trimmed and cut into 0.5-inch pieces
• 2 cups fresh strawberries, hulled and sliced
• 3/4 cup granulated sugar, for the fruit layer
• 2 tbsp cornstarch
• 1 tsp vanilla extract, pure, not imitation
• 15 1/4 oz yellow cake mix, one standard box, dry and unprepared
• 1/2 cup unsalted butter, cold, cut into thin slices
• 1 tsp lemon zest, from about half a lemon

Instruction

1

Preheat your oven to 350 degrees F (175 degrees C). Lightly grease a 9x13-inch baking dish with butter or nonstick spray.

2

In a large bowl, combine the sliced strawberries, chopped rhubarb, granulated sugar, cornstarch, vanilla extract, and lemon zest. Toss until the fruit is evenly coated.

3

Pour the fruit mixture into the prepared baking dish and spread it into an even layer.

4

Sprinkle the dry yellow cake mix evenly over the top of the fruit layer. Do not stir or mix it in.

5

Arrange the cold butter slices in a single layer over the top of the dry cake mix, covering as much of the surface as possible.

6

Bake uncovered for 45 to 55 minutes, until the top is golden brown and the fruit is bubbling around the edges.

7

Remove from the oven and let the cake rest for at least 15 minutes before serving. The filling will thicken as it cools.

8

Serve warm with a scoop of vanilla ice cream or a dollop of whipped cream, and enjoy.

Equipment

• 9x13-inch baking dish
• Large mixing bowl
• Sharp knife and cutting board
• Microplane or zester
• Measuring cups and spoons

Notes

Store leftovers covered at room temperature for up to 1 day, or refrigerate for up to 4 days. Reheat individual portions in the microwave for 30 to 45 seconds. For a make-ahead option, prep the fruit layer the night before and refrigerate it covered. Add the cake mix and butter just before baking. Frozen rhubarb works well here too, but thaw and drain it thoroughly first to avoid a watery bottom.

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Variations and Swaps Worth Trying

One of the best things about this strawberry rhubarb cake recipe is how flexible it is. Here are a few variations to keep in your back pocket:

• Swap the cake mix. White cake mix is light and neutral. Strawberry cake mix leans into the berry flavors. Spice cake mix adds a warm, autumnal depth.
• Add oats to the topping. Scatter half a cup of rolled oats over the dry cake mix before the butter for a more cobbler-like crunch.
• Stir in a pinch of cinnamon or cardamom to the fruit layer for extra warmth.
• Use a mix of berries. Blueberries, raspberries, or blackberries all play beautifully with rhubarb if your strawberry supply is running low.

However you make it, this is one of those easy strawberry dessert recipes you will come back to every single season.