Chocolate Oreos
By Flourtown Bakery Café

(Recipe adapted from Flour by Joanne Chang, chronicle books)
 
This dough can be made, rolled and wrapped and kept in the fridge raw for up to a week or frozen for up to a month.  Thoroughly defrost before continuing with the recipe.
 
Makes 16-18 sandwiched cookies
 
Ingredients
225g unsalted butter, melted and cooled
150g granulated sugar
1 tsp vanilla extract
200g plain chocolate (70%), broken into pieces, melted and cooled
1 egg
210g plain flour
90g cocoa powder
1 tsp salt
½ tsp baking powder
 
For the vanilla filling

115g unsalted butter, softened
230g icing sugar
1 tsp vanilla extract or vanilla bean paste
1 tsp whole milk
 
Method

1. Whisk the melted butter and granulated sugar until well combined. Whisk in the vanilla and melted chocolate until smooth looking? Whisk in the egg until thoroughly mixed.
2. In a clean bowl sift the flour, cocoa powder, salt and baking powder. Using a wooden spoon stir the flour mixture into the wet chocolate mixture. The more you stir the dough will become very stiff so then switch to mixing with your hands until it forms a smooth dough. Let to sit a room temperature for 1 hour to firm up.
3. Transfer to a large sheet of parchment paper (about 38cm square). Shape into a rough log about (10inches) 25cm long and (2.5inches) 6.5cm in diameter. Place the log at the edge of the paper and roll the paper around the log.  Roll into a smoother log keeping it the same length. Chill for 2 hours, rerolling in the paper every half hour to keep it’s shape and stop it from forming a flat bottom.
4. Preheat the oven to 190C/fan 170C/gas 5. Grease a baking tray (2?) and line with parchment paper.  Cut the dough into 5mm slices and place on the lined tray at least 2.5cm apart.
5. Bake for 10-12 minutes or until the middle of the cookies are just firm to the touch. Cool on the baking sheet to room temperature.
6. Meanwhile make the filling, in a large bowl beat the butter until soft and completely smooth. Add the icing sugar and vanilla extract until the mixture is completely smooth. Add the milk and continue beating until soft and smooth. Spoon into a piping bag fitted with a large plain nozzle.
7. Pipe some filling onto the middle of one cookie. Top with a second cookie and press together to spread the filling towards the edges. Repeat to fill all the cookies. 
8. Keep in an air tight container in a cool place.