Chocolate Bumpy Cake

I almost stopped in my tracks when I saw a picture of Chocolate Bumpy Cake on Shauna Severs Instagram feed.  Never before had a seen a cake like this and I've seen a lot of them in my lifetime!  She's included the recipe in her upcoming baking cookbook "Midwest Made" but if you don't want to wait for the book's publication in October you can find it on TheKitchn.Com.  When I read the accompanying story about the cake's origins I was even more intrigued.  

Chocolate bumpy cake was created in 1913 in Detroit, Michigan by the Sanders Candy company.  It's basically a devil's food cake topped with rows of buttercream "bumps" which are then covered in fudge frosting.  While the cake components are pretty basic, visually I find it absolutely stunning.  The stark contrast of the white buttercream bumps against the dark cake and glossy icing are so beautiful.   

 

What I can't understand is how this bumpy cake escaped my notice all these years.  Given that I know at least five people with ties to Michigan I'm very surprised that I'd never heard of it before.  I blame them for keeping me in the dark!

As expected the cake tasted great and was super moist and chocolate-y.  My only disappointment with the one I made for this blog post was that the fudge frosting wasn't as glossy and shiny as I would have liked.  Perhaps I let it cool too much before pouring it over the cake so the signature "bumps" were lost?  I think I was concerned that the warm fudge frosting would melt the cold buttercream bumps.   Guess I'll have to make it again to course correct!  :-)

Chocolate Bumpy Cake

Makes one 9x13-inch cake

CAKE

2 cups all-purpose flour

2 cups granulated sugar

1/2 cup unsweetened cocoa

1 1/2 teaspoons baking soda

3/4 teaspoon fine salt

1 cup buttermilk, room temperature

1/2 cup hot coffee or hot water

1/2 cup vegetable or canola oil

2 large eggs

2 teaspoons vanilla extract 

FILLING

1 cup granulated sugar

1/4 cup cornstarch

1/8 teaspoon fine salt

1 cup whole milk

1 teaspoon vanilla extract

1/2 cup unsalted butter, at cool room temperature

 

ICING

1 cup unsalted butter, divided

1 cup granulated sugar

1/2 cup buttermilk

1/3 cup dark corn syrup

1/3 cup unsweetened cocoa

1/4 teaspoon fine salt

1 cup powdered sugar

1 teaspoon vanilla extract

CAKE: Position a rack to the center of the oven and heat it to 350°F. Spray a 9 x 13-inch light-colored metal baking pan with cooking spray.  [I lined mine with a big sheet of parchment paper.]

In a large bowl, whisk together the flour, granulated sugar, cocoa powder, baking soda, and salt. 

In a medium bowl, whisk together the buttermilk, coffee or water, oil, eggs, and vanilla. Pour the wet ingredients in the dry. Beat with an electric mixer until smooth. Pour the batter into the prepared pan. Bake until a toothpick inserted in the center of the cake comes out clean, 30 to 35 minutes. Set the pan on a wire rack to cool completely. Meanwhile, prepare the filling.

FILLING: In a 2- to 2 1/2- quart saucepan, whisk together the granulated sugar, cornstarch, and salt. Whisk in the milk. Bring to a boil over medium-high heat; boil for 1 minute. Remove from the heat and whisk in the vanilla. Transfer to the clean bowl of an electric mixer and let cool completely. Beating with the paddle attachment on medium speed, beat in 1 tablespoon of butter at a time. Increasing the speed to medium-high, beat until light and fluffy and resembling whipped cream, about 5 minutes.    

When the cake has cooled completely, load the filling into a pastry bag fitted with a 1-inch large round tip. Pipe nine 9-inch lines crosswise over the cake, 1 inch apart. Freeze until the filling is solid, at least 30 minutes. 

ICING: When the filling is solid, keep the cake in the freezer while you prepare the icing: In a 2- to 2 1/2- quart saucepan, combine 1/2 cup of the butter and the sugar, buttermilk, corn syrup, cocoa powder, and salt. Place the pan over medium-high heat and bring the mixture to a boil. Clip a candy thermometer to the side of the pan and cook until the mixture reaches 235°F— no higher. Whisk in the remaining butter, 1 tablespoon at a time. Stir in the powdered sugar and vanilla, whisking until the icing is smooth.   

Remove the cake from the freezer. Immediately pour the icing in waterfall-like ribbons over the surface of the cake. If needed, gently rewarm any icing clinging to the pan, and pour it again. Freeze the cake until the icing is set, about 15 minutes, or refrigerate until ready to serve. Store any leftovers tightly covered in the refrigerator for up to a week.