Try this Whoopie Pies recipe
Cocoa powder carries natural acidity that requires both baking soda and baking powder to achieve proper lift. Without enough alkaline agents reacting against the cocoa solids, the resulting cakes would remain dense and heavy instead of developing the characteristic soft, cake-like crumb required for sandwiching fillings. Historically associated with Pennsylvania Dutch bakeries, these treats balance structural integrity with a tender bite through careful fat selection and mixing techniques.
Creaming shortening with granulated sugar introduces microscopic air pockets into the batter, which expand under the heat of a 350 degrees F oven when the leavening gases release. Alternating the addition of the sifted dry ingredients with cold milk prevents gluten overdevelopment, keeping the cakes tender while maintaining enough structure to support the weight of the filling without collapsing. Drop the batter onto greased cookie sheets and bake for 10 to 15 minutes, watching for the surfaces to spring back gently when pressed with a fingertip before transferring them to wire racks to cool completely.
Shortening whips into a stable, aerated emulsion when combined with confectioners' sugar because solid fats trap sugar crystals and air simultaneously without dissolving them. Raw egg whites can provide additional volume through albumin proteins stretching into a stable foam, though culinary adjustments allow whole eggs or alternative fats if raw proteins are omitted. Spread the filling generously onto the flat interior side of one cooled cake and press a matching half gently on top to distribute the center evenly across the edges.