1Heat oven to 400ºF. Mix flour, brown sugar, baking powder, cinnamon, baking soda, nutmeg, salt and cloves in medium bowl. Cut in margarine, using fork or pastry blender, until mixture looks like fine crumbs. Stir in sweet potato, carrot, yogurt and vanilla just until dough leaves side of bowl.
2Place dough on lightly floured surface; gently roll in flour to coat. Knead lightly 10 times. Roll dough 1/2 inch thick. Cut with 2 1/2-inch cookie cutter dipped into flour, or cut into diamonds with knife. Place about 1 inch apart on ungreased cookie sheet. Brush with egg white; sprinkle with granulated sugar.
3Bake about 20 minutes or until edges are light brown. Immediately remove from cookie sheet to wire rack. Serve warm.