To prepare a baking dish for easy removal of bar cookies: First, prepare pan with butter or cooking spray. Cut two sheets of parchment paper that measure several inches larger than the pan you're using. Lay each piece of paper in pan and make crease marks on two opposing edges of pan to mark your fold lines. Remove paper and fold each side at fold lines. Place paper with open folded edges face down in pan and fold long edges up the side of the pan. Repeat with second sheet of parchment, laying it in pan the opposite direction. You should have four edges sticking up out of the pan and, once filled with the dough and baked, will come out very easily by simply lifting the edges of the paper, up and out of the pan. Voila!