In a bow mix butter, sugar, brown sugar, salt, baking powder, baking soda, coffee powder and vanilla. Mix well.
Add milk and mix it until incorporated.
Sift in flour and cocoa and mix to form a firm and crumbly dough.
Preheat oven to 175 C.
Roll out portion of the dough to 1/8” thick and cut out cookies with a 2” cookie cutter. I used a 1 ¾” cutter.
Gently remove the cookies with a spatula and transfer to a greased baking tray. You can place cookies without any gap as it does not spread.
Bake the cookies for 10-12 minutes.
Remove on to a wire rack and let them cool completely. Finish off the remaining cookies.
Add all the ingredients in a bow.
Beat it until fluffy and light.
Transfer the filling into a disposable plastic bag.
On the wire rack, invert half of the cookies.
Snip the end of the plastic bag.
Pipe out generous portions of filling on the inverted cookies.
Place the other cookie on top of the filling and press.
Arrange the finished cookies in an airtight jar and refrigerate for 2 hours.
Serve along with a cup of coffee.