6. Prepare Icing: Place butter in saucepan and heat until lightly browned. Remove from heat and add Kahlua & whipping cream. Whisk in powdered sugar until you have the consistency that you desire (you should be looking for a thick, smooth icing that is still pourable). Pour on top of cooled brownies and spread to edges to cover completely. Refrigerate until set. Chilled brownies are easiest to cut… use a large, sharp knife, wipe clean after each cut, and you’ll get nice, clean cuts.