Ingredients

• 3 ounces bittersweet (60% cacao) chocolate, finely chopped (about 1/2 cup)
• 1/4 cup (about 7/8 ounce) unsweetened cocoa
• 1/3 cup hot brewed coffee
• 3/4 cup plus 2 tablespoons granulated sugar
• 3/4 cup (about 3 1/4 ounce) all-purpose flour
• 3/4 teaspoon kosher salt
• 1/2 teaspoon baking soda
• 2 large eggs, at room temperature
• 1/2 cup canola oil
• 1/4 cup sour cream, at room temperature
• 1 teaspoon vanilla extract
• 1 cup unsalted butter, softened
• 12 ounces white chocolate bars, chopped, melted and cooled slightly (2 cups chopped)
• 2 cups unsifted powdered sugar
• 1 teaspoon vanilla extract
• 1/4 teaspoon kosher salt