In large bowl, whisk together flour, cornstarch, ginger, cinnamon, baking soda, cloves, nutmeg and salt; set aside.
Using electric mixer, beat together butter and brown sugar until light and fluffy, scraping down side of bowl as needed; beat in egg. Beat in molasses and vanilla. Gradually beat in flour mixture.
On lightly floured work surface, divide dough in half. Flatten into disks; wrap in plastic wrap. Refrigerate for at least 2 hours before rolling out.
Preheat oven to 350°F (180°C). Working with one portion of dough at a time, roll out dough on lightly floured work surface into 1/4-inch (5 mm) thickness. Using 4 -inch (10 cm) gingerbread man cookie cutter, cut out cookies. Transfer to parchment paper–lined baking sheet, about 2 inches apart, rerolling scraps once.
Bake cookies, in two batches, for 8 to 10 minutes or until lightly golden and tops are set. Let cool in pan for 10 minutes; transfer to rack and let cool completely.
Using electric mixer, beat icing sugar, vanilla sugar, cream of tartar and egg white on low speed until combined. Gradually add enough water, 1 tbsp (15 mL) at a time, to thin out icing. Spoon icing into piping bag; pipe onto cookies.
Decorate cookies with sprinkles and candy canes.