Preheat oven to 175C.
Spray a baking pan with non-stick spray.
Microwave chocolate and butter until melted (about 30 to 40 seconds). Then 10 seconds blast if not melted.
Stir in cocoa powder, and coffee powder, then set aside.
Whisk sugar, eggs, vanilla extract, salt, and peanut butter together.
Whisk in chocolate mixture.
Fold in flour until just combined.
Fold in chopped peanut butter cups.
Pour into prepared pan.
Bake 35-40 minutes, until skewer inserted comes out with some moist crumbs.
Allow to cool completely before slicing into squares.