In a medium bowl, whisk together flour, cornstarch, baking soda, salt and baking powder. Set aside. In another medium bowl, whisk the coffee and cocoa powder until smooth. Set aside. In a large bowl, beat the shortening, sugar, vanilla and eggs with a mixer on medium speed until pale and fluffy (for about 2 minutes). Alternately add the flour mixture and the coffee mixture to the bowl in 3 stages, beating to combine after each addition.
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