Lightly spoon the flour into a measuring cup, and level with a knife. Combine flour, sugar, and salt in a bowl, stirring with a whisk.
Place butter in a medium bowl; beat with a mixer at medium speed until light and fluffy. Add flour mixture, beating at low speed. Add milk and vanilla; beat until blended. Pat the dough into a 4-inch circle; wrap in plastic wrap, and chill 30 minutes.
Preheat oven to 350°.
Unwrap and place dough on plastic wrap. Cover dough with an additional sheet of plastic wrap. Roll dough, still covered, into an 8-inch circle. Place dough on a baking sheet coated with cooking spray. Cut dough into 16 wedges, cutting into, but not through, dough. Pierce dough several times with a fork. Bake at 350° for 20 minutes or until lightly browned. Cool on pan 5 minutes. Cut into wedges. Cool completely on a wire rack.