Serves 15 to 20
SANDERS CONFECTIONERY IS A DETROIT INSTITUTION. SINCE 1875, SANDERS HAS cranked out legendary chocolates, candies, dessert sauces, ice cream treats and more, as retail products and in their brick and mortar locations. One of Sanders’s most famous and beloved items is its Bumpy Cake, a combination of deeply chocolate cake and unique little rails of vanilla buttercream crossing the top, under a slick of glossy fudge icing. You can buy the cake in some grocery stores in the Midwest, but it’s even better when you set aside the time to make it yourself. There are a few steps involved here, but there’s no better birthday gift for your favorite Michigander.
Nonstick cooking spray for pan
2 cups/256 g unbleached all-purpose flour, spooned and leveled
2 cups/400 g granulated sugar
½ cup/48 g unsweetened cocoa powder*
1½ teaspoons baking soda
¾ teaspoon fine sea salt
1 cup/225 g well-shaken buttermilk, at room temperature
½ cup/113 g hot brewed coffee or hot water
½ cup/113 g vegetable or canola oil
2 large eggs
2 teaspoons pure vanilla extract
1 cup/200 g granulated sugar
¼ cup/32 g cornstarch
⅛ teaspoon fine sea salt
1 cup/225 g whole milk
1 teaspoon pure vanilla extract
½ cup/113 g unsalted butter, at cool room temperature
1 cup/225 g unsalted butter, divided
1 cup/200 g granulated sugar
½ cup/113 g well-shaken buttermilk
⅓ cup/113 g dark corn syrup
⅓ cup/32 g unsweetened cocoa powder
¼ teaspoon fine sea salt
1 cup/120 g confectioners’ sugar
1 teaspoon pure vanilla extract
Prepare the cake: Position a rack to the center of the oven and preheat it to 350°F/180°C. Spray a 9 × 13-inch/23 × 33 cm light-colored metal baking pan with nonstick cooking spray.
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, 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: In a 2- to 2½-quart/1.9 to 2.4 L 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 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/2.5 cm large round tip. Pipe nine 9-inch/23 cm lines crosswise over the cake, 1 inch/2.5 cm apart. Freeze until the filling is solid, at least 30 minutes.
When the filling is solid, keep the cake in the freezer while you prepare the icing: In a 2- to 2½-quart/1.9 to 2.4 L saucepan, combine ½ cup/113 g 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/113°C—no higher. Whisk in the remaining butter, 1 tablespoon at a time. Stir in the confectioners’ 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.
*My first choice here is a half-and-half mix of regular Dutch-processed and black cocoa powders, for dynamite color and flavor. But if all you have is natural cocoa, that will work, too.