In a large bowl, cream butter and brown sugar until light and fluffy. Beat in egg and vanilla. Combine the flour, baking soda and salt; gradually add to the creamed mixture. Refrigerate for at least 2 hours or until easy to handle. , Meanwhile, in a large saucepan, combine the dates, water and sugar. Cook and stir over medium heat until thickened, about 5 minutes. Stir in walnuts and cherries. Cool completely. , Divide dough in half; roll one portion between two sheets of waxed paper into a 12-in. x 10-in. rectangle. Spread with half of the filling. Roll up into a tight jelly roll, starting with a long side; wrap in plastic. Repeat with remaining dough and filling. Cover and refrigerate for 2 hours or until firm. , Unwrap and cut into 1/4-in. slices with a sharp knife; place 1 in. apart on greased baking sheets. Bake at 375° for 8-10 minutes or until lightly browned. Remove to wire racks to cool.