Halloween Layer Cake

INGREDIENTS

• 1 3/4 cups cake flour
• 1 teaspoon baking soda
• 1 teaspoon salt
• 1 1/2 cups white sugar
• 1/3 cup shortening
• 1 cup buttermilk
• 3 egg whites
• 4 (1 ounce) squares unsweetened chocolate, melted
• 1 teaspoon butter
• 1/3 cup butter, softened
• 1 1/2 tablespoons orange zest
• 1 teaspoon lemon zest
• 1/4 teaspoon salt
• 1 egg yolk
• 4 cups sifted confectioners' sugar
• 1 tablespoon orange juice
• 2 teaspoons lemon juice