Lightly spoon flour into dry measuring cups; level with a knife. Combine the flour and next 7 ingredients (flour through cloves) in a bowl, and set aside. Combine granulated sugar and butter in a large bowl; beat at medium speed of a mixer 5 minutes. Add molasses and egg white; beat well. Add flour mixture to sugar mixture; beat at low speed until well-blended. Divide dough in half, and shape each half into a ball, and wrap in plastic wrap. Chill 1 hour.
Preheat oven to 350°.
Working with 1 half of dough at a time (keep remaining half chilled until ready to use), roll the dough to a 1/8-inch thickness on a heavily floured surface; cut with a 2 1/2-inch boy or girl cookie cutter. Place gingerbread cookies 1 inch apart on baking sheets coated with cooking spray. Arrange currants on cookies as buttons. Bake at 350° for 8 minutes. Remove from pans; cool on wire racks.
Combine the powdered sugar, lemon juice, and vanilla in a small bowl. Spoon into a decorating bag or a heavy-duty zip-top plastic bag with a tiny hole snipped in 1 corner of bag, and decorate as desired.