Beat butter in a large bowl with an electric mixer on medium to high speed for 30 seconds. Add brown sugar and vanilla; beat until combined. Beat in as much of the flour as you can. Stir in remaining flour and 1/2 cup chopped pine nuts.
Shape dough into 1-inch balls. Place balls 1-1/2 inches apart on an ungreased cookie sheet; flatten gently until 1/2 inch thick. Bake in a 350 degree F oven for 10 to 12 minutes or until lightly browned. Transfer to wire racks to cool.
If desired, pipe frosting in a peak on each cookie and sprinkle with additional pine nuts. Makes about 60.