In a small bowl, cream butter and brown sugar until crumbly. Beat in egg and vanilla. Gradually add cookie mix and mix well.
Place egg white and cashews in separate shallow bowls. Shape dough into 1-in. balls. Dip in egg white, then roll in cashews.
Place 1 in. apart on ungreased baking sheets. Using the end of a wooden spoon handle, make an indentation in the center of each cookie. Fill with preserves. Bake at 350° for 10-12 minutes or until set. Remove to wire racks to cool. Store in an airtight container.