In a large bowl, cream butter and sugar until light and fluffy. Beat in the lemon juice, zest and vanilla. Combine the flour, rosemary and salt; gradually add to creamed mixture and mix well.
Shape into two 12-in. rolls; wrap each in plastic. Freeze for 30 minutes or until firm. Cut into 1/4-in. slices. Place 2 in. apart on ungreased baking sheets. Bake at 350° for 8-10 minutes or until edges begin to brown. Cool for 2 minutes before removing from pans to wire racks. Store in an airtight container.