Whoopie Pie Cake

Cake:
1 cup margarine
2 cups sugar
2 1/4 cups all-purpose 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 all-purpose flour
2 cups granulated sugar
8 tablespoons butter
1 tablespoon vanilla extract
1 cup solid vegetable shortening

Heat oven to 350 degrees F. Grease two 9-inch 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 extract and shortening. Add the cooled flour mixture. Whip for at least 3 minutes until creamy. This makes enough icing to generously frost a 2-layer cake.

Source: Becky's Diner, Portland, Maine