Preheat oven to 350 degrees.
Add the melted butter, brown sugar, and granulated sugar to the bowl of a stand mixer and beat until well combined.
Beat in the egg and vanilla extract.
Dump in the flour, baking soda, and salt. Mix until combined. Dough will be soft.
Stir in the candy and white chocolate chips.
Use a large cookie scoop to scoop out 12 balls of dough.
Bake for 10 minutes exactly. Do not overbake. Cookies may look a bit underdone, but they will set up as they cool.
Let cookies set on the baking sheet for at least 5 minutes before eating.
Store, tightly covered, for up to 5 days.