Homemade Oreos!

Makes 25 to 30 sandwich cookies

For the chocolate wafers:
2 1/2 cups (310 grams) all-purpose flour
1 cup (90) grams, but cocoa weights can vary greatly) unsweetened Dutch process cocoa
2 teaspoons baking soda
1/2 teaspoon baking powder
1/2 teaspoon salt
3 cups (400 to 600 grams) sugar
1 1/2 cups plus  (2 1/2 sticks or 280 grams) room-temperature, unsalted butter
2 large eggs

For the filling:
1/2 cup (1 stick or 110 grams) room-temperature, unsalted butter
1/2 cup (100 grams) vegetable shortening
4 cups (480 grams) sifted confectioners’ sugar
4 teaspoons (20 ml) vanilla extract 

1. Preheat oven to 375°F.
2. In a food processor, or bowl of an electric mixer, thoroughly mix the flour, cocoa, baking soda and powder, salt, and sugar. While pulsing, or on low speed, add the butter, and then the egg. Continue processing or mixing until dough comes together in a mass.
3. Take rounded teaspoons of batter and place on a parchment paper-lined baking sheet approximately two inches apart. With moistened hands, slightly flatten the dough. Bake for 9 minutes, rotating once for even baking. Set baking sheets on a rack to cool.
4. To make the cream, place butter and shortening in a mixing bowl, and at low speed, gradually beat in the sugar and vanilla. Turn the mixer on high and beat for 2 to 3 minutes until filling is light and fluffy.
5. To assemble the cookies, in a pastry bag with a 1/2 inch, round tip, pipe teaspoon-size blobs of cream into the center of one cookie. Place another cookie, equal in size to the first, on top of the cream. Lightly press, to work the filling evenly to the outsides of the cookie. Continue this process until all the cookies have been sandwiched with cream.

Credit to Smitten Kitchen