Rum Raisin Tart (Brown Butter) BY HELEN S. FLETCHER, ON August 5, 2012 COPYRIGHT, HELEN S. FLETCHER, 2013. ALL RIGHTS RESERVED. ALL PHOTOS BY T. MIKE FLETCHER, UNLESS OTHERWISE NOTED. Place the butter in a small pan. Bring to a boil and boil gently until the butter until the edges of the butter in the pan start browning and turns a medium brown.