You can find them in most places in Maine with flavors such as pumpkin or red velvet for the cookies. The fluffy cream center can vary as well. Though vanilla is the most common flavor, chocolate, strawberry, mint or peanut butter fluff is just delicious! The Maine House votes that The Lobster Shack has the best Whoopie Pies in Maine!
Cool the cake layers 5 minutes, then remove them from pans and cool them completely on a wire rack.
To make the icing, pour the milk into a stainless steel saucepan over medium heat. Gradually whisk in flour until a thick paste forms. Do not scorch! Remove from stove and cool this mixture in the refrigerator.
In a separate bowl, mix the sugar, butter, vanilla, and shortening. Add the cooled paste. Whip for at least 3 minutes until creamy. This makes enough icing to generously frost a 2-layer cake.