Bumpy Cake (Chocolate Cake With Vanilla Buttercream And Chocolate Fudge)

Ingredients

• 1 tablespoon unsalted butter
• 1/2 cup plus 2 tablespoons unsweetened dutch process cocoa powder
• 1/2 cup hot black coffee
• 1/2 cup canola oil
• 1 cup buttermilk
• 1 tablespoon pure vanilla extract
• 1 1/2 teaspoons baking soda
• 2 eggs, lightly beaten
• 3/4 cup dark brown sugar, firmly packed
• 3/4 cup white sugar
• 2 cups all-purpose flour
• 1/4 cup unsalted butter
• 1/4 cup vegetable shortening
• 2 1/2 cups confectioners sugar
• 1 teaspoon vanilla extract
• 1/2 cup buttermilk, room temperature
• 1 cup sugar
• 1/3 cup dark corn syrup
• 1/3 cup unsweetened dutch process cocoa powder
• 1/4 teaspoon salt
• 16 tablespoons (2 sticks) unsalted butter, cut into tablespoon-sized pieces
• 2 1/2 cups powdered sugar