Stir together flour and salt in medium-size bowl.
Beat butter and sugar in large bowl until smooth and creamy. Beat in egg. Beat in peppermint extract and vanilla.
On low speed, beat in flour mixture. Wrap dough in plastic wrap; refrigerate 1 hour.
Heat oven to 375°F.
Shape dough into 1-inch balls; place on lightly greased baking sheets.
Bake in 375°F oven for 10 to 12 minutes or until bottoms are lightly browned. Transfer cookies to wire racks to cool completely.
To top, brush with melted white chocolate; dip lightly in crushed candy canes. Place on waxed paper to harden.