Beat first 5 ingredients with a mixer at medium speed until well blended. Lightly spoon flour into dry measuring cups; level with a knife. Add flour and milk to sugar mixture, mixing well.
Shape dough into 21 (1-inch) balls. Place balls 2 inches apart on baking sheets coated with cooking spray. Flatten cookies with the bottom of a glass. Bake at 350° for 10 minutes. Remove from pans; cool completely on wire racks.
Combine powdered sugar, water, and lemon juice. Spoon glaze in center of each cookie; sprinkle with sugar sprinkles.