This easy Rhubarb Dump Cake is one of the simplest spring desserts to make. Using just a few pantry staples and fresh or frozen rhubarb, this comforting cake-cobbler hybrid comes together in minutes. The sweet-tart rhubarb filling bubbles beneath a buttery cake mix topping, creating a nostalgic dessert perfect for potlucks, family gatherings, or using up seasonal rhubarb.
I make this recipe every rhubarb season because it requires almost no prep and always gets great feedback. Serve it warm with vanilla ice cream or cooled from the fridge — either way, this classic dump cake is a reliable crowd-pleaser.
If you enjoy rhubarb, try other recipes like healthy orange rhubarb muffins with buttermilk, frosted rhubarb cookies with cream cheese frosting, strawberry rhubarb lemonade, or rhubarb fruit leather.
Why You Will Love Rhubarb Dump Cake
A simple box of cake mix becomes a crisp, buttery topping with only butter and a few minutes of assembly. This dessert delivers comfort and flavor with minimal effort.
- Requires only a few simple ingredients
- No mixing bowls needed
- Perfect balance of sweet and tart
- Ideal for spring and early summer
- Make-ahead friendly for parties
- Works with fresh or frozen rhubarb
Ingredients Needed for Rhubarb Dump Cake
- Chopped rhubarb — fresh from the garden if available. If you prefer another fruit, cherry or apple pie filling can be used instead.
- Sugar — regular granulated sugar. Use sugar substitutes only if you know the correct conversion.
- Yellow cake mix — you can substitute a sugar-free mix if desired.
- Butter, cold and sliced — unsalted butter is best for controlling salt, though some recipes use pats of butter rather than melted.
- See the recipe card below for exact measurements.
How to Make Rhubarb Dump Cake
Step 1: Grease a 9 x 13 (or 9 x 9) glass baking dish. Spread the chopped rhubarb in an even layer and sprinkle the sugar over it.
Step 2: Evenly sprinkle the dry cake mix over the rhubarb and sugar layer.
Step 3: Slice cold butter into tablespoon-sized pieces and distribute them evenly over the cake mix so the topping browns and crisps while baking.
Step 4: Bake in a 350°F oven for 40–60 minutes, or until the topping is golden and crisp and the filling is bubbly. Check at 40 minutes and add time as needed.
Variations to Try
- Strawberry Rhubarb Dump Cake — Replace part of the rhubarb with sliced strawberries for a sweeter, colorful version.
- Rhubarb Dump Cake Without Jello — Omit gelatin and add a pinch of cinnamon or a splash of vanilla for a more natural fruit flavor.
- From-Scratch Topping — Make a simple streusel from flour, sugar, and baking powder instead of using a boxed mix.
- Different Cake Mix Flavors — Try spice, butter, or vanilla cake mix for new flavor combinations.
- Frozen Rhubarb — No need to thaw; just add a bit more baking time if the filling is very cold.
Rhubarb Dump Cake Expert Tips
- Do not mix the layers — keep them separate so the topping bakes into a crisp crust.
- Cut rhubarb into small, even pieces so it cooks uniformly.
- Let the cake cool slightly or chill before slicing for cleaner portions.
- Use extra butter pieces for an extra-crispy top.
- Taste the rhubarb first — very tart stalks may require a bit more sugar.
⭐ Serving Suggestions
- Serve warm with vanilla ice cream or whipped cream.
- Top with custard or a dollop of crème fraîche.
- Bring to BBQs, potlucks, or family gatherings.
- Works beautifully for spring celebrations like Mother’s Day or Easter.
- A lovely way to use garden rhubarb.
Recipe FAQs
Yes. Frozen rhubarb works well and does not need to be thawed first; just allow a bit more bake time if the filling is very cold.
Store in an airtight container in the refrigerator for up to three days. Reheat gently before serving if desired.
A powdery top usually means the butter or liquid didn’t distribute evenly. Make sure butter pieces are spread across the surface so the cake mix can absorb moisture while baking.
The topping can be slightly gooey when first removed from the oven due to melted butter. Let the cake sit for a while to set for cleaner slices.
Other Recipes To Try
-
Jersey Mikes Chicken Salad Recipe
-
Air Fryer Recipes for Beginners
-
Air Fryer Cookie Dough
-
Crock Pot Swamp Potatoes
If you try this Rhubarb Dump Cake or any recipe from this site, please leave a star rating and share your experience in the comments. I enjoy hearing how it turned out!
Rhubarb Dump Cake
Description
This Rhubarb Dump Cake is extremely easy—no mixing required. Simply layer the ingredients in a pan and let the oven do the work.
Ingredients
- 4–5 cups chopped rhubarb
- ½ cup sugar
- 1 box yellow cake mix
- 2 sticks butter, cut into cold cubes
Instructions
- Preheat the oven to 350°F. Grease a 9 x 13 (or 9 x 9) glass baking dish.
- Spread chopped rhubarb in the dish and sprinkle evenly with sugar.
- Sprinkle the cake mix evenly over the rhubarb and sugar.
- Distribute the cold butter pieces over the cake mix.
- Bake 40–60 minutes, until the top is golden and the filling bubbles. Let rest before serving.
Notes
Make-ahead: You can assemble ahead and refrigerate; bake when ready. The topping may be slightly soft right out of the oven—allow time to set for cleaner slices.
Nutrition
- Calories: 208
- Sugar: 20 g
- Fat: 9 g
- Saturated Fat: 3 g
- Carbohydrates: 33 g
- Fiber: 1 g
- Protein: 1 g
Recipe adapted from Our Fun with Five