Ingredients

  • 1 1/2 cups all-purpose flour
  • 1/2 cup cocoa powder
  • 1 1/4 teaspoons baking soda
  • 1/4 teaspoon salt
  • 1 1/4 cups granulated sugar
  • 1 1/4 cup sour cream
  • 2/3 cup vegetable oil
  • 2 large eggs
  • 1 teaspoon pure vanilla extract
  • 1 teaspoon instant espresso powder
  • 20 tablespoons unsalted butter, softened
  • 1 cup confectioners sugar
  • 3/4 cup plus 1 tablespoon cocoa powder
  • Pinch salt
  • 2/3 cup light corn syrup
  • 1 teaspoon pure vanilla extract
  • 10 ounces bittersweet chocolate, melted and cooled

Method

  • Adjust oven rack to middle position and preheat oven to 350°F. Line bottoms of 2 9-inch cake pans with parchment paper and lightly coat the inside with non-stick pan spray. Sift flour, cocoa, baking soda, and salt into large bowl; set aside. In medium bowl, whisk sugar, sour cream, oil, eggs, vanilla, and espresso powder until smooth.
  • Whisk wet ingredients into dry ingredients until smooth. Evenly divide into pans and bake until cake is just firm and toothpick inserted into center comes out with moist crumbs, about 25 minutes. Let cake cool in pans for 15 minutes, then remove cakes from pans to completely cool on wire rack, about 1 hour.
  • Meanwhile, make the frosting: In food processor, process butter, confectioners sugar, cocoa, and salt until completely combined and smooth. Add corn syrup and vanilla and combine until smooth, scraping down sides of bowl as necessary. Add chocolate and process until just smooth.
  • Place one cake (top side up) on serving plate. Spread about 1 cup frosting onto cake. Place second cake (bottom side up) on top. Frost top and sides with remaining frosting. Use back of spoon soup spoon to make swirls on cake. Decorate if desired and serve.