In a large mixing bowl, beat together butter and sugar with electric mixer until well combined and creamy. Beat in egg and vanilla until well combined.
In a separate small bowl mix together flour, baking powder, and salt until well combined. Beat into butter/sugar mixture until well combined. Wrap dough up in plastic wrap and refrigerate for 2-3 hours or until well chilled (can refrigerate overnight or up to a few days).
Preheat oven to 350 degrees F. Line baking sheets with parchment paper or silpats (or lightly spray with nonstick spray).
Break dough apart into small pieces and roll with hands until about 2 inches in length. Place on prepared baking sheets. Bake at 350 degrees F for about 11-14 minutes or until lightly browned underneath. Cookies will flatten as they cook. Place cookies on wire racks to cool.
Meanwhile, place white chocolate in microwave safe bowl and microwave on half power in 30 second intervals, stirring after each interval, until smooth. (Be careful, the white chocolate can seize and become a mess rather quickly) Stir in peppermint extract.
Dip cookies in white chocolate. Place on waxed paper (or silpats or parchment paper) and sprinkle crushed candy canes on top of chocolate. Cool completely until chocolate sets.
SNAPPY TIPS: To save time make a big batch of this dough and make multiple kinds of cookies. The cookies freeze well.SNAPPY SUBSTITUTIONS: Instead of candy canes you could also use starlight mints, sprinkles, or any crushed candy. If use something such as sprinkles that don’t have a peppermint flavor I would suggest adding a little more peppermint extract to the white chocolate. You could also substitute other types of chocolate for the white chocolate such as dark chocolate or semi-sweet chocolate.