It isn't often that you find a "one egg cake" such as this... one ... cake or 24 cupcakes. Note: You may vary ... with confectioners' sugar. Mix flour with sugar. Stir in ... and store in refrigerator.
Mix until smooth using beater at ... blueberry (or cherry) pie filling mix on top of the 12 cupcakes, covering the tops. Refrigerate for several hours.