Beat the butter with an electric mixer until creamy, then gradually add the sugar, beating until light and fluffy. Add the egg, vanilla, and milk, and beat thoroughly. Sift the dry ingredients together and add to the mixture. Blend well. Remove dough from bowl onto a floured surface. With floured hands, shape into a log about 4 inches in diameter. Wrap well and refrigerate for at least 3 hours.
Preheat the oven to 350 degrees. Slice cookie dough 1/8 inch thick and place flat 2 inches apart on ungreased cookies sheet. Bake 8 to 10 minutes until centers are set. Remove from cookies sheets and cool on a wire rack.
c.1997, M.S. Milliken & S. Feniger, all rights reserved