Preheat oven to 350 degrees. Sift the flour, salt and baking powder in a bowl and set aside. Cream butter and sugar on medium high until fluffy about 5 minutes. Add eggs one at time mixing well after each. Add your dry ingredients until mixed. Add vanilla. Pour onto floured waxed paper and roll into a log. Chill until set then cut into 1/2 inch slices and bake for about 12 minutes until light browned on a greased cookie sheet. You may also drop by tablespoons if in a hurry.