Ingredients:

  • 2 cups all-purpose flour
  • 2 cups granulated sugar
  • 1 cup unsalted butter
  • 4 tablespoons unsweetened cocoa powder
  • 1 cup boiling water
  • 0.5 cup sour cream
  • 2 large eggs
  • 1 teaspoon baking soda
  • 1 tablespoon vanilla extract
  • 0.5 teaspoon salt
  • 0.5 cup unsalted butter (for frosting)
  • 4 tablespoons unsweetened cocoa powder (for frosting)
  • 6 tablespoons whole milk (for frosting)
  • 3 cups powdered sugar
  • 1 teaspoon vanilla extract (for frosting)
  • 1 cup chopped pecans

Instructions:

  1. Preheat oven to 350°F (175°C) and grease an 18x13-inch jelly roll pan.
  2. In a large saucepan, combine 1 cup butter, 4 tablespoons cocoa powder, and 1 cup water. Bring to a boil over medium heat, whisking constantly until smooth. Remove from heat.
  3. In a large mixing bowl, whisk together the flour, granulated sugar, baking soda, and salt. Pour the hot chocolate mixture over the dry ingredients and stir until well combined.
  4. In a small bowl, whisk the sour cream, eggs, and 1 tablespoon vanilla extract. Add this to the cake batter and stir until smooth.
  5. Pour the batter into the prepared pan and bake for 18-22 minutes, or until a toothpick inserted into the center comes out clean.
  6. While the cake is baking, prepare the frosting: In a saucepan, bring 0.5 cup butter, 4 tablespoons cocoa, and 6 tablespoons milk to a boil. Remove from heat and whisk in the powdered sugar, 1 teaspoon vanilla, and pecans.
  7. Pour the warm frosting over the cake immediately after removing it from the oven. Let cool completely before slicing.