American Chocolate Bumpy Cake

Ingredients:

Chocolate cake

• 3/4 cup cocoa powder
• 1 tbsp instant espresso powder
• 3/4 cup vegetable oil
• 1 cup of hot water
• 1/4 cup whole milk
• 1 tbsp vanilla extract
• 1.5 tsp of baking soda
• 3/4 tsp baking powder
• 3/4 teaspoon coarse salt
• 3 large eggs
• 2 cups granulated sugar
• 2 cups premium flour
• Cooking spray to grease the pans
• Special equipment: pastry bag, 1 cm round tip, caramel thermometer

Sugar-butter cream

• 2 cups powdered sugar
• 110 g (8 tbsp) unsalted butter, room temperature
• A pinch of coarse salt
• 1 tbsp vanilla extract
• 1–2 tbsp whole milk, if needed

Chocolate glaze

• 1 and 3/4 cups powdered sugar
• 0.5 cup buttermilk or 10% drinking cream
• 1 tbsp vanilla extract
• 0.5 cup cocoa powder
• 1/3 cup dark corn syrup
• A pinch of coarse salt
• 220 g (1 cup) unsalted butter, cut into small pieces, at room temperature

Preparation:

1. Preheat oven to 350°F (175°C). Spray a 9 x 13-inch baking dish with cooking spray.
2. Chocolate cake:
   
   In a large bowl, combine the cocoa powder and instant espresso. Pour in the vegetable oil, water, milk, and vanilla extract and mix until smooth. Add the baking soda, baking powder, salt, and eggs and whisk until smooth. Stir in the sugar. Add the flour and mix until smooth. Pour the batter into the prepared baking pan.
3. Bake until a toothpick inserted into the center comes out with a few crumbs, 33–35 minutes. Transfer to a wire rack to cool completely, about 1 hour. Freeze until set, about 1 hour.
4. Sugar-butter cream:
   
   Meanwhile, insert a 1 cm round tip into a pastry bag. In the bowl of a stand mixer fitted with the paddle attachment, combine the sugar, butter, and salt (or in a large bowl if using a hand mixer). Mix on low speed until smooth. Add the vanilla, increase the speed to medium-high, and beat until smooth and thick but pliable. Adjust the consistency with milk if necessary. Transfer the buttercream to the pastry bag. If the buttercream becomes too soft and warm, refrigerate until completely set, about 10 minutes.
5. Turn the cake over so the short side is facing you and pipe 7 horizontal rows of buttercream on top, spacing them 2.5–4 cm apart. Return the cake to the freezer until the buttercream is set, about 30 minutes.
6. Chocolate glaze:
   
   In a medium saucepan, combine the powdered sugar, buttermilk, and vanilla. Add the cocoa powder, corn syrup, and salt and bring to a boil over medium heat, stirring constantly. Attach a candy thermometer to the pan, reduce the heat to medium-low, and cook until the mixture reaches 230°F (115°C). Remove the pan from the heat and add the butter a few pieces at a time, stirring constantly, until the glaze is smooth. Let cool slightly, about 10 minutes.
7. Pour half the frosting over the buttercream layers, tilting the pan slightly so the entire surface is covered and the frosting runs down the sides of the cake. Freeze the cake until the frosting sets, about 10 minutes. Spread another layer of chocolate frosting and refrigerate the cake for 20 minutes to set before serving. Use a sharp knife to slice the cake, as the frosting is sticky, especially around the edges. The cake can be stored, covered, in the refrigerator for up to 1 week..