5-Ingredient Strawberry Rhubarb Dump Cake
This strawberry rhubarb dump cake is the dessert you make when you want something warm, jammy, and a little bit tangy without pulling out a single mixing bowl. You toss the fruit together, pour it in a dish, and shake the cake mix right over the top.
The oven transforms that dry mix into a buttery, crackly crust with soft, cakey pockets where the fruit juices seeped up. It smells like a bakery and tastes like the best parts of a cobbler with none of the work.
What Makes This Dump Cake So Good
The rhubarb stays tart while the strawberries melt into a bright, jammy sauce. The top bakes up crisp and golden on the peaks, soft and almost pudding-like where the butter soaked into the cake mix.
It takes maybe 10 minutes to get into the oven and then you just let the heat do its thing. The hardest part is waiting for it to cool enough to eat.
No creaming, no cutting in butter, no egg to crack. You literally dump the ingredients into the baking dish in layers and walk away. That’s it.
Ingredients
- 1 lb fresh strawberries, hulled and halved: use peak-season berries for the sweetest flavor
- 12 oz rhubarb, sliced ½-inch thick: if stalks are thick, peel away any tough strings
- ⅔ cup granulated sugar: adjust based on how sweet your fruit tastes
- 2 tbsp cornstarch: this thickens the juices so the cake isn’t soupy
- 15.25 oz box yellow cake mix: a plain yellow cake mix is classic, but a white or butter recipe box works too
- ½ cup unsalted butter, melted: unsalted gives you control over the saltiness
Variations / Substitutions
- Swap the fruit: any berry or stone fruit works here, just keep the total weight about the same (around 28 oz). Peaches and blueberries are a favorite.
- Use a different cake mix: a spice cake mix leans into fall flavors, or a chocolate mix takes it in a richer direction.
- Add citrus: a teaspoon of orange zest tossed into the fruit brightens everything.
- Make it gluten-free: use your favorite gluten-free yellow cake mix and follow the box weight.
If you love warm fruit desserts with a crunchy topping, our easy apple crisp recipe is another one to keep in your back pocket.
How to Make Strawberry Rhubarb Dump Cake
Step 1: Toss the Fruit with Sugar and Cornstarch
Preheat your oven to 350°F (175°C). In a large bowl, combine the 1 lb halved strawberries, 12 oz sliced rhubarb, ⅔ cup granulated sugar, and 2 tbsp cornstarch. Toss until the fruit is evenly coated and the cornstarch has dissolved into the sugar.
The mixture will look a little dry on the fruit, with no visible liquid pooling at the bottom. Don’t worry about that now. The strawberries and rhubarb will release a lot of juice as they bake, and the cornstarch will turn it into a thick sauce.
Step 2: Assemble the Dump Cake
Grease a 9×13-inch baking dish lightly with butter or spray. Dump the fruit mixture into the dish and spread it into an even layer. Open the 15.25 oz box of yellow cake mix and sprinkle the dry mix evenly across the top. Try to cover all the fruit, right out to the edges. Slowly drizzle the ½ cup melted unsalted butter over the cake mix, making sure you hit most of the surface. Some dry spots are fine.
The top will look uneven, with some clumps of butter-soaked mix and some powdery patches. That’s exactly how it should look. As it bakes, the butter melts down into the cake mix and the fruit juices bubble up, turning those dry patches into tender pockets.
Step 3: Bake Until Golden and Bubbly
Slide the dish into the preheated oven and bake for 45 to 50 minutes. You’ll know it’s done when the top is deeply golden brown and the fruit is bubbling thickly around the edges, with a jam-like consistency. The center might still have a few spots of pale, dry mix, but that’s fine as long as the fruit is visibly bubbling.
Your kitchen will fill with a sweet, caramelized fruit smell around the 30-minute mark. If the top browns too quickly before the fruit bubbles, you can tent the dish loosely with foil for the last 10 minutes.
Step 4: Spoon the Cake Into Bowls
Let the dump cake rest for at least 10 minutes on a cooling rack. The bubbling will settle and the fruit layer will thicken. Use a large spoon to scoop generous servings into bowls, getting some of that golden topping and the jammy fruit in each spoonful.
A scoop of vanilla ice cream on the side is never a bad idea. The cake is best served warm, while the top still has a little crunch from the oven.
Tips for the Best Dump Cake
- If you want a topping with more distinct buttery crunch, cut the ½ cup cold butter into small cubes and dot them over the cake mix instead of melting it. The top will be craggier and more cookie-like.
- Let the baked cake stand for 10 to 15 minutes before you serve it. The juices need that time to set, so your first scoop doesn’t slide into a puddle.
- For a deeper fruit flavor, macerate the strawberries and rhubarb with the sugar for 15 minutes before adding the cornstarch. You’ll pull out more juice and concentrate the sweetness.
- Tenting with foil is your friend if the top darkens too fast. Every oven runs a little differently, so check the color at 35 minutes and drape a piece of foil loosely over the top if needed.
Storing Leftover Dump Cake
- Refrigerate: cover the dish tightly or transfer to an airtight container and refrigerate up to 4 days.
- Reheating: warm individual portions in the microwave for about a minute, or place the whole dish in a 350°F (175°C) oven until heated through.
- Serve cold: the cake is surprisingly good straight from the fridge, like a fruit-studded coffee cake.
Frequently Asked Questions
Can I use frozen fruit?
Yes, you can use frozen strawberries and rhubarb without thawing them first. Increase the cornstarch to 3 tablespoons to handle the extra liquid from the frozen fruit, and expect the bake time to be 5 to 10 minutes longer.
Can I cut back on the sugar?
You can reduce the granulated sugar to ⅓ cup if your strawberries are very sweet and you prefer a tarter dessert. The fruit will still be saucy and the cake mix will still work, but the overall flavor will be much sharper.
Do I need to grease the baking dish?
The melted butter in the topping adds enough fat that the cake doesn’t typically stick, but a quick spritz of cooking spray or a thin swipe of butter on the dish makes cleanup much easier.
What if I don’t have a 9×13-inch dish?
An 11×7-inch or even a 9×9-inch baking dish works. You may need to add 5 to 10 minutes to the bake time because the fruit layer will be deeper and take a little longer to bubble through.
Strawberry Rhubarb Dump Cake Recipe
Ingredients
Method
- Preheat oven to 350°F (175°C). In a large bowl, toss the strawberries, rhubarb, sugar, and cornstarch until well combined.
- Dump the fruit into a lightly greased 9×13-inch baking dish. Sprinkle the dry cake mix evenly over the fruit, then slowly drizzle the melted butter over the top.
- Bake for 45 to 50 minutes, until the top is golden and the fruit is bubbling thickly at the edges. If the top browns too fast, tent loosely with foil.
- Let the cake rest for 10 minutes, then spoon into bowls and serve warm.
Notes
