Chocolate Macaroon Tunnel Cake Recipe

Ingredients

• 0.5 cup shortening
• 1.75 cups white sugar
• 1 egg yolk
• 2 teaspoons vanilla extract
• 4 eggs
• 2 cups sifted all-purpose flour
• 0.5 cup unsweetened cocoa powder
• 1 teaspoon baking soda
• 1 teaspoon salt
• 0.75 cup cold water
• 0.5 cup sour cream
• 1 egg white
• 0.25 cup white sugar
• 1 cup flaked coconut
• 1 tablespoon all-purpose flour
• 1 teaspoon vanilla extract
• 2 cups sifted confectioners' sugar
• 1 tablespoon butter, softened
• 2 tablespoons milk, or as needed