Preheat oven to 375 degrees. Cover two cookie sheets with parchment paper.
In a food processor (or stand mixer) combine flour, cocoa powder, baking soda, baking powder, salt, sugar, butter, and eggs. Blend until the dough comes together and everything is moistened.
Take 1 teaspoon of dough at a time and roll into a ball. Place on parchment-lined cookie sheet and flatten slightly. Place each ball 2 or 3 inches apart. Continue making 48 balls. Cook in two batches so that each cookie sheet gets used twice.
Bake in the preheated oven for 9 minutes. Bake one cookie sheet at a time and place it on the center rack in the oven. Let cool for a few minutes and then slide the parchment paper off the cookie sheet onto a cooling rack and allow the cookies to cool completely. Re-line the cookie sheet for the second batch.
Make the filling by mixing together butter, brown sugar, vanilla, salt, and flour in a medium-size mixing bowl. Add water 1 TB at a time until the dough is the same consistency as a frosting. Stir in *chocolate chips if desired.
Lay out cooled cookies in rows of two. Use a piping bag and wide-mouth tip to fill one side of the cookie and use another cookie to sandwich. Or use a knife and spread the cookie dough on the cookie.
Store in an airtight container and enjoy with a big glass of milk.
Notes
For traditional Oreo filling: 1/2 cup shortening 2 cups powdered sugar 1 teaspoon vanilla extract