Preheat the oven to 350 F. In a medium bowl, whisk together flour, salt, and baking soda. In a large bowl, combine butter and sugar until fluffy.
Add in the egg and peppermint extract until smooth. Add in the flour mixture, and mix until it is fully combined.
Fold in the white chocolate chips and crushed candy canes. Roll the cookie dough into balls, and place them onto a large ungreased baking sheet at least 2-inches apart.
Bake for 10-12 minutes. Remove from the oven and place one candy cane kiss on each cookie.