Preheat oven to 375° F.
Cream together the butter, granulated sugar and brown sugar.
Add the egg, buttermilk and vanilla. Mix until light in color and creamy.
Add in the dry ingredients (flour, crushed Oreos, cocoa, baking soda and salt), mix into the dough. Mix until completely combined.
Mix in the white chocolate chips until evenly distributed.Scoop the cookie dough out into 1 1/2 tbsp portions (#40 scoop).
Roll first in granulated sugar and then in the powdered sugar and then arrange on a parchment or silicone lined cookie sheet. Flatten each cookie slightly so it looks like a hockey puck. Repeat with remaining dough.
Bake at 375° F for 7-10 minutes, until the cookies flatten slightly, and begin to crackle when they are ready to come out of the oven.
Allow the cookies to cool on the pan for 5 minutes before transferring to a wire cooling rack.