1. In food processor, put flour and butter and process until mixture looks crumbly.
2. Add sugar and vanilla, then process until you get a dough consistency.
3. Remove from food processor carefully, then put dough on floured surface and knead slightly into a 2 inch thick tube about 12 inches long. Wrap in plastic food wrap and put in refrigerator for at least 1 hour.
4. When ready to bake, preheat oven to 400 degrees and grease a couple cookie sheets.
5. Unwrap the cookie dough and slice thin discs of cookie dough, about 1/4 inch thick. Put them on cookie sheets leaving an inch or more between each cookie.
6. Bake on a center rack in the oven for 8 to 11 minutes or until cookies are light golden brown. Remove from oven and allow to rest for 3 or 4 minutes, then slide onto rack to cool. Sprinkle with confectioner's sugar when on rack if desired.