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This bumpy cake is a nostalgic chocolate sheet cake with thick vanilla filling piped in bold rows, then finished with a smooth cooked chocolate frosting that settles into the grooves. The texture contrast is the whole point here. Expect soft cake, creamy filling and a glossy chocolate top that sets up nicely for clean slices. It’s the kind of bake that looks like it came from Sanders Confectionery, even though the steps to make it yourself are fairly straightforward.
Why You’ll Love It
This bumpy cake is a chocolate sheet cake topped with piped vanilla filling and finished with a smooth chocolate ganache that sets into the classic ridges.
Iconic slice: Those piped rows give you the signature look as soon as you cut into it.
Deeper chocolate flavor: Coffee in the batter boosts the chocolate taste without making it taste like coffee.
Clean serving: A short chill helps everything set so slices look neat.
No fancy decorating: The “bumps” do all the work and still look impressive.
Other easy cake recipes you may enjoy include Italian love cake, twinkie cake, ding dong cake, gooey butter cake and chocolate roll cake.
Chocolate Bumpy Cake Ingredients
A complete list of ingredients and amounts can be found in the recipe card below.
Chocolate cake mix: Creates a sturdy chocolate base for the layers and means you don’t have to weight out ingredients like dark corn syrup, baking soda or cake flour. Devil’s food or dark chocolate cake mix can be used for a deeper flavor. I used the Baker’s Corner brand of cake mix. My recipe called for 1 cup water, ½ cup vegetable oil and 3 eggs. I replaced the water with coffee. Follow your box’s instructions and replace the water with coffee or leave it as is if you don’t have coffee on hand.
Brewed coffee: Deepens the chocolate flavor. Use regular coffee or espresso powder and let the hot coffee cool before using.
Vegetable oil: Keeps the cake soft and moist.
Eggs: Add structure for clean slices.
Butter: Makes the filling rich and creamy. Use salted or unsalted butter.
Butter flavored shortening: Used to help the frosting stay sturdy underneath the chocolate topping.
Vanilla extract: Adds a sweet, warm flavor.
Powdered sugar: Thickens the filling for piping. I recommend sifting your confectioners’ sugar for a smoother result.
Heavy cream: Smooths the filling and frosting texture.
Granulated sugar: Sweetens the cooked chocolate frosting.
Unsweetened cocoa powder: Gives the chocolate ganache topping a deep chocolate flavor. Dutch processed cocoa can be used for a darker, smoother finish.
How to Make Bumpy Cake
For more detailed instructions with weights and measurements, jump to the printable recipe card.
Prepare the pan: Preheat oven and grease a rectangular baking pan with cooking spray.
Mix the batter: Combine the cake mix, coffee, oil and eggs with an electric or stand mixer with paddle attachment until smooth.
Bake and cool: Spread the batter evenly in the prepared pan, bake until a toothpick inserted into the cake comes out clean, then cool completely on a wire rack.
Make the filling: Beat the butter, shortening and vanilla, then blend in powdered sugar and cream until thick and pipeable.
Pipe the rows: Pipe thick, even rows of filling across the cooled cake.
Chill the cake: Refrigerate briefly so the filling firms up.
Cook the frosting: Heat the chocolate frosting ingredients together in a medium saucepan while stirring constantly until smooth.
Cool slightly: Let the frosting cool until warm and pourable.
Finish the cake: Pour the frosting over the cake to completely cover and chill until set before slicing.
Substitutions and Variations
Cake mix swap: Use devil’s food or dark chocolate mix for a deeper chocolate flavor.
No coffee: Use hot water instead, the cake still works but the chocolate flavor is lighter.
Heavy cream: Half and half can be used in the filling, but heavy cream gives better structure and flavor.
Oil substitute: Canola or avocado oil both work as neutral swaps.
Shortening swap: Plain shortening can be used with no impact on texture. If you don’t have shortening on hand, you can simply replace it with butter.
Fudge frosting: Swap the vanilla buttercream for slightly warm fudge frosting or fudge icing or chocolate fudge or any other flavor you want.
Cocoa change: Dutch processed cocoa gives a darker color and smoother chocolate finish.
Serving Suggestions
With a cold drink: Pineapple agua fresca or state fair lemonade would be a good pairing.
With a hot drink: Enjoy bumpy cake with a pistachio latte or Irish cream coffee.
With savory snacks: If you’re creating a buffet spread, add Cajun shrimp deviled eggs and aleppo pepper chicken bites to the table.
With other sweet treats: Chocolate coconut magic bars and Nanaimo bars are always good.
How to Store
Refrigerate: Store the cake covered in the refrigerator for up to 4 days.
Freeze: Wrap well and freeze for up to 2 months.
Thaw: Thaw overnight in the refrigerator before serving.
Top Tips
Cool cake to room temperature: Any warmth will soften the filling and blur the bumps.
Chill before pouring: Cold filling helps the chocolate layer sit on top instead of melting through.
Stir the frosting nonstop: Constant stirring prevents scorching and keeps the texture smooth.
Let it cool a bit: Warm and pourable is the goal, hot will melt the filling.
Clean cuts: Use a warm knife and wipe between slices for the neatest pieces.
Homemade Bumpy Cake FAQs
Chill the filled cake before pouring the chocolate frosting and keep the filling thick enough to hold its shape.
You need the vanilla buttercream frosting rows quite tall and large, as this creates the classic bumpy look and allows the ganache to settle naturally between them. Wider, taller lines make the classic look more obvious once the chocolate settles. I cut the piping bag further back than if I was simply using a frosting tip. You want about a 1 ½ inch wide hole in your piping bag. If you don’t have a piping bag fitted with large round tip or large open circle tip, you can just use a Ziploc bag with the corner snipped off.
Chocolate Bumpy Cake Recipe
Bumpy Cake
Equipment
- Electric Mixer or Stand Mixer
- Baking Dish 9 x 13-Inch
- Pastry Bag or Ziploc Bag
Ingredients
For the Cake
- 1 Box chocolate cake mix, 15 ¼-Ounce
- 1 Cup coffee, freshly brewed and cooled
- ½ cup vegetable oil
- 3 eggs, large
- nonstick cooking spray, to grease pan
For the Vanilla Frosting
- ½ Cup salted butter, softened
- ¼ Cup shortening, butter flavor or unflavored
- 1 Teaspoon vanilla extract
- ½ Teaspoon salt
- 4 Cups powdered sugar
- 2 to 3 Tablespoons heavy cream
For the Chocolate Ganache Topping
- 1 Cup heavy cream
- 1 ½ Cups granulated sugar
- 6 Tablespoons salted butter
- ¼ Cup unsweetened cocoa powder
- 1 Teaspoon salt
Instructions
- Preheat the oven to 350°F.
Prepare the Cake Batter
- In a large bowl, mix the coffee, cake mix, vegetable oil and eggs together until well incorporated.
- Spread the batter evenly into a greased 9 x 13-inch baking pan.
Bake the Cake
- Bake according to package instructions (mine called for 29 to 33 minutes) or until a toothpick inserted comes out clean.
- Cool completely.
Make the Vanilla Frosting
- Beat the butter, shortening, vanilla and salt until combined.
- Sift in 2 cups of powdered sugar and the heavy cream and mix.
- Pour in the last 2 cups of powdered sugar and beat until light and fluffy.
- Add more heavy cream as needed. The frosting should be thick so that it keeps its structure, but still loose enough to be easily piped on to the cake.
Add the Bumps
- Pipe or spread the vanilla frosting in thick rows across the cooled cake.
- Place into the refrigerator while preparing the chocolate frosting.
Make the Chocolate Topping
- In a medium sized saucepan over medium heat, add heavy cream, granulated sugar, butter, cocoa powder and salt.
- Stir until mixture reaches a rolling boil.
- Set a timer for 3 minutes and stir continuously for that time.
- Take off of the heat.
- Set aside to cool for about 10 to 15 minutes or until cooled enough to pour over the frosting without melting it.
Add the Ganache Topping
- Pour the chocolate ganache over the cake, allowing it to settle between the frosting rows.
- Refrigerate for 15 to 20 minutes until set before slicing.
Notes
Chill before pouring: Cold filling helps the chocolate layer sit on top instead of melting through.
Stir the frosting nonstop: Constant stirring prevents scorching and keeps the texture smooth.
Let it cool a bit: Warm and pourable is the goal, hot will melt the filling.
Clean cuts: Use a warm knife and wipe between slices for the neatest pieces.
Nutrition
This is the kind of chocolate cake people hover around in the kitchen, waiting for the first piece and it’s a well known cake from Sanders Confectionary Company. The piped filling gives every slice its trademark look, and that smooth chocolate topping settles in neatly once it chills. Keep your bumpy cake in the fridge, slice what you need, and you’ve got a crowd-pleasing dessert that holds up beautifully over a few days.
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