Prepare cake mix as directed on package for cupcakes, adding espresso powder and 1 tablespoon of the vanilla.
Bake as directed on package for cupcakes. Cool completely.
Meanwhile, stir cream cheese, sugar, salt and remaining 1 teaspoon vanilla in medium bowl until well blended. Beat cream in large bowl with electric mixer on medium speed until soft peaks form. Add 1/4 of the whipped cream to cream cheese mixture. Stir gently with spatula until well blended. Add remaining whipped cream. Stir gently to incorporate whipped cream. Frost cupcakes. Sprinkle tops with cocoa powder.