Cream butter and granulated sugar in bowl of electric mixer fitted with paddle attachment until blended. Mix in combined flour, base cake, cocoa and salt. Spread dough in a thin layer on parchment paper-lined sheet pan. Refrigerate until firm enough to roll. Roll to 1/8-inch thickness on lightly floured surface. Using a 2-inch round cutter, cut into 50 circles. Place on parchment paper-lined pans. Refrigerate until ready to use.

Bring water, butter, sugar and salt to a boil in heavy saucepan. Remove from heat and add flour all at once. Stir quickly to incorporate. Reduce heat to low. Return pan to heat and stir until mixture lightly coats bottom of pan and pulls away from the sides of the pan. 

Pour mixture into bowl of electric mixer fitted with paddle attachment. Mix on medium speed for 1 min. to reduce heat of mixture slightly. Add eggs, a few at a time, to warm mixture, mixing until eggs are fully incorporated before adding additional eggs. The mixture should fall off spatula and have a nice sheen. (Note: if mixture is too stiff add an extra egg. If the mixture is loose enough, you may not need all of the eggs called for.)

Make a template for the cream puffs, using a 2-inch round cutter on parchment-paper lined baking sheets. Put prepared cream puff dough in a pastry bag fitted with a large round tip. Pipe dough inside template. Place 1 chocolate dough disc on top of puff mixture. Bake in a preheated 425ºF standard oven 30 to 35 min. or until firm and fully dry. Remove from oven and allow to cool completely before filling.

Cut top 2/3rds of cream puff off and set aside. Whip cream in large bowl of mixer fitted with whip attachment to medium stiff peaks. Fold in OREO Base Cake. Fill pastry bag fitted with a large star tip and fill bottom of each cream puff. After filling, place OREO Small Cookie Pieces around the bottom portion of the whipped cream mixture. Set top of cream puff on whipped cream at an angle. Serve immediately or refrigerate.