Lingkan Reang
Preheat oven to 180°C and line a 9x10 inch pan with parchment paper.
Melt butter, then mix with brown sugar, regular sugar, salt, and vanilla using a whisk or electric mixer.
Add eggs and beat until frothy, then mix in coffee dissolved in hot water.
Fold in flour and cocoa powder, then gently incorporate chopped chocolate.
Spread batter in the prepared pan and bake for 25-30 minutes until the top is shiny and crispy.
Let cool for 10 minutes in the pan, then remove, cool further, and slice into pieces.