Whoopie Pie Cake

The Whoopie Pie was invented in Maine back in the 1920s: Like a giant, squishy Oreo cookie, it is two discs of chocolate cake sandwiching a creamy-sweet filling. One of the most popular desserts at Becky's Diner in Portland, Maine, is a cake she makes inspired by the Whoopie pie, frosted with a low-cost icing she found while browsing through a World War II era cookbook. The marshmallow-soft icing gives this cake an evocative old-fashioned character, totally unlike a modern "sinful" boutique gateau.

Recipe Source: Becky's Diner

Preparation Time: 20 minutes
Cook Time: 50 minutes
Servings: 8

Ingredients:

Cake:
1 cup margarine
2 cups sugar
2-1/4 cups flour
1 teaspoon baking soda
1 teaspoon salt
1-1/4 cups buttermilk
3 eggs
9 tablespoons cocoa powder

Icing:
2 cups whole milk
3/4 cup white flour
2 cups granulated sugar
8 tablespoons butter
1 tablespoon vanilla
1 cup solid vegetable shortening

Directions:

Preheat oven to 350 degrees.
Grease 2 9" round cake pans.
Beat together the margarine and sugar. Add flour, baking soda, and salt. Mix slowly, gradually adding buttermilk. Beat 2 full minutes.
Add eggs, then gradually add cocoa, beating another 2 minutes, stopping occasionally to scrape the sides of the bowl.
Pour batter into prepared pans and bake about 40 minutes, until center springs back when gently pushed.
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.