In a medium saucepan, melt butter over medium heat. Add sugar and whisk 1-2 minutes to dissolve sugar. Add chocolate chips, vanilla extract, and coffee extract and whisk until smooth. Remove from heat, and set aside to allow to cool slightly.
In a large bowl, mix flour, cocoa powder, salt and baking powder.
Once the chocolate mixture has cooled slightly, add eggs one at a time, whisking well in between each addition.
Pour the chocolate mixture into the flour mixture and stir until combined. Cover and chill for at least one hour.
Preheat the oven to 350 degrees, and line a baking sheet with parchment paper. Scoop a rounded tablespoon of batter for each cookie, and bake for 10-12 minutes. Remove the cookies from the oven and transfer them to a cooling rack. Store in an airtight container.