Rhubarb Dump Cake

Posted on March 1, 2026

introduction

This easy, nostalgic Rhubarb Dump Cake is pure comfort in a 9×13 — tart rhubarb meets sweet cake mix for a dessert that practically makes itself. Warm, bright, and perfect for sharing, it’s the kind of recipe that pins beautifully and becomes a family favorite fast. For a snack or breakfast companion, try pairing flavors with a light bite like Blueberry Cheesecake Protein Bites for a balanced treat after a slice.

Why You’ll Love This Rhubarb Dump Cake :

Bright, tangy rhubarb balances perfectly with sweet yellow cake mix.
Super simple — no mixing bowl required for the filling.
Fast to prep: throw it together in under 15 minutes.
Crowd-pleasing warm dessert that pairs beautifully with ice cream.
Great for potlucks and busy weeknights when you want dessert with minimal fuss.

Ingredients Needed :

Fruit

4 cups chopped rhubarb (fresh or thawed frozen)

Sweetener & flavor

1 cup granulated sugar
1 (3 oz) package strawberry gelatin (Jell-O)

Dry mix & topping

1 box yellow cake mix (not the ingredients, the dry mix)

Liquids & fat

1 cup water
½ cup unsalted butter, melted

If you like cinnamon-sweet ideas for weekend brunch, check out this easy Cinnamon Roll Pancakes Recipe for a delicious companion dish.

Step-by-Step Instructions :

Preheat your oven to 350°F (175°C) and grease a 9×13-inch baking dish.
Layer the chopped rhubarb evenly in the bottom of the dish and sprinkle the sugar over it.
Sprinkle the strawberry gelatin powder over the rhubarb and then add the cake mix on top without stirring.
Drizzle water and melted butter over the top evenly, ensuring all areas are covered.
Bake for 45-50 minutes until golden and bubbly around the edges.
Let it rest for 10 minutes before serving, optionally with vanilla ice cream.

Serving Suggestions Rhubarb Dump Cake

Serve warm with a scoop of vanilla ice cream or whipped cream.
Sprinkle toasted chopped walnuts or pecans on top for crunch.
For a lighter pairing at brunch, try a bowl of Carrot Cake Overnight Oats alongside a small slice.
Leftovers are great cold or reheated — they also freeze well in portions.

Tips for Success Rhubarb Dump Cake

Chop rhubarb into uniform 1/2-inch pieces so it cooks evenly.
If your rhubarb is extra tart, add an extra 1–2 tbsp sugar to taste.
Use high-quality butter and drizzle slowly so the cake mix soaks and forms a crisp top.
For gluten-free, swap in a gluten-free yellow cake mix and check gelatin brand for GF labeling.
Want a sweeter, cinnamon-kissed top? Lightly sprinkle cinnamon over the cake mix before drizzling butter; for more technique tips, see this Cinnamon Roll Pancakes — The Ultimate Guide for inspiration on balancing flavors.

variation (if any)

Strawberry-Rhubarb: Add 1–1½ cups chopped fresh strawberries to the rhubarb layer.
Crumb Topping: Replace the cake mix with a simple oat crumble (oats, flour, brown sugar, butter) for a crisp streusel.
Mini Dump Cakes: Bake in 6–8 ramekins for individual servings; reduce bake time to 30–35 minutes.
Lower Sugar: Use ¾ cup sugar and a no-sugar-added gelatin for a less-sweet version.

FAQs

Q: Can I use frozen rhubarb?
A: Yes — thaw and drain excess liquid, then pat lightly before mixing. Slightly more moisture may increase bake time.

Q: Can I substitute another cake mix flavor?
A: Yellow or white mixes work best, but spice or butter cake mixes can add a richer flavor — adjust sugar if needed.

Q: How should I store leftovers?
A: Cover and refrigerate up to 4 days. Reheat single portions in the microwave or oven until warm.

Q: Can I make this ahead for a party?
A: Yes — assemble in the dish, cover, and refrigerate up to 24 hours; bake when ready (you may need a few extra minutes).