Preheat oven to 350F.
In a medium size bowl or stand mixer, cream butter and sugar together until light and fluffy (about 2-3 minutes).
Add egg, vanilla and peppermint oil. Mix well. Scrape down side of bowl.
Add the flour, baking soda and salt. Mix the dough only until the ingredients are incorporated. Don't over mix the batter.
Fold in the white chocolate chips and crushed puffy peppermints.
Using a size 40 portion scoop, form dough into balls (about 18).
Place 9-12 cookies on a parchment lined baking sheet.
Bake at 350F for 8-10 minutes or until the bottom edges of the cookie begin to brown. Immediately after removing the baking sheet from the oven, tap the sheet down to release any loose air. This will help the cookies be soft and chewy.
Let cookies cool for 3-5 minutes before moving to a cooling rack or paper towel.
Store cookies in an airtight bag or container to keep freshness.