Weigh or lightly spoon flour into dry measuring cups; level with a knife.
Combine flour and next 6 ingredients (through salt), stirring with a whisk.
Combine butter and 1/4 cup sugar in a medium bowl, and beat with a mixer at medium speed until light and fluffy (about 3 minutes). Beat in 3 tablespoons milk, molasses, and vanilla extract.
Add flour mixture to butter mixture, and beat on low speed until blended. Shape dough into a 6-inch disk. Cover and chill for 30 minutes.
Lightly coat hands with cooking spray. Shape dough into 30 balls (about 2 teaspoons each).
Place remaining 1/2 cup sugar in a shallow bowl.
Roll dough balls in sugar; place 2 inches apart on baking sheets coated with cooking spray. Flatten balls slightly with the bottom of a glass.
Bake at 350 for 12 minutes or until lightly browned. Cool on pans 4 minutes.
Remove cookies from pans; cool completely on wire racks.