Grease and line a pan with parchment paper. Set aside.
Preheat the oven to 350°F / 180°C.
In a medium saucepan, add the butter, chocolate, coffee powder and half of the cocoa powder. Melt over medium heat, whisking until everything has melted together. Set aside to cool.
In a bowl, whisk together the flour, baking powder and half of the cocoa powder. Set aside.
In a large bowl, mix the sugar and salt together. Add the eggs all at once and beat on high with an electric mixer for about 5 minutes. The mixture should be thick like cake batter.
Add the melted chocolate mixture to the egg mixture and beat until well incorporated.
Gently fold in the flour mixture until just combined. Don’t overmix.
Pour into the prepared pan and even out the top.
Bake for about 15- 25 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs on it.
Allow it to cool completely to room temperature, then lift out of the pan.
Cut into squares and store in an airtight container in the refrigerator for up to a week.