Four-Layer Chocolate Birthday Cake with Milk Chocolate Ganache & Nutella Buttercream Recipe - (4.4/5

Ingredients

• CAKE:
• 1/2 cup (1 stick) unsalted butter, room temperature, plus more for pan
• 2 cups all-purpose flour, plus more for pan
• 6 ounces bittersweet chocolate, chopped
• 1 cup brewed coffee
• 2/3 cup unsweetened cocoa powder (not Dutch process)
• 3 large eggs, room temperature
• 1 cup buttermilk, room temperature
• 2 teaspoons vanilla extract
• 1 3/4 teaspoons kosher salt
• 1 1/2 teaspoons baking powder
• 1 1/2 teaspoons baking soda
• 2 1/2 cups (packed) light brown sugar
• 1/4 cup vegetable oil
• GANACHE:
• 8 ounces bittersweet chocolate, chopped
• 1 cup heavy cream
• 1/4 teaspoon kosher salt
• 1/4 cup (1/2 stick) unsalted butter, cut into pieces, room temperature
• BUTTERCREAM:
• 3 large egg yolks, room temperature
• 1 large egg, room temperature
• 1/2 teaspoon kosher salt
• 3/4 cup sugar
• 1 1/4 cups (2 1/2 sticks) unsalted butter, room temperature, cut into pieces
• 1 cup Nutella
• 1 teaspoon vanilla extract
• Sprinkles (for decorating; optional)
• SPECIAL EQUIPMENT:
• A candy thermometer