Zutaten:

• 2 sticks (8 ounces) plus 1 tablespoon unsalted butter, divided
• 2 cups all-purpose flour
• 1 cup granulated sugar
• 1 cup packed light brown sugar
• 1 teaspoon baking soda
• 1/2 teaspoon kosher salt
• 1/3 cup Dutch-processed unsweetened cocoa powder
• 1 cup boiling water
• 1/2 cup buttermilk
• 2 large eggs
• 1 teaspoon vanilla extract
• 1/2 cup raw or toasted pecan halves
• 1 1/2 sticks (12 tablespoons) unsalted butter
• 1/4 cup Dutch-processed unsweetened cocoa powder
• 6 tablespoons whole or 2% milk
• 1 teaspoon vanilla extract
• 2 1/2 cups powdered sugar