Making Whoopie Pies

Ingredients

• 1 cup shortening
• 2 cups sugar
• 2 eggs
• 1 cup whole milk, soured with 1 teaspoon vinegar
• 2 teaspoons vanilla extract
• 4 cups flour
• 1 cup dark cocoa powder
• 1 teaspoon baking powder
• 2 teaspoons salt
• 1 teaspoon baking soda
• 1 cup hot water
• 1 cup whole milk
• 4 tablespoons flour
• 1/4 pound butter, softened
• 1-1/2 cups shortening
• 3 cups powdered sugar
• 1 teaspoon vanilla extract