Preheat your oven to 350°F (175°C). Line two baking sheets with parchment paper and set aside.
In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy. This usually takes about 2–3 minutes.
Add the egg and vanilla extract. Mix until fully combined and smooth.
In a separate bowl, whisk together the flour, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing just until combined. Don’t overmix here.
Gently fold in the crushed chocolate sandwich cookies and white chocolate chips using a spatula.
Scoop about 2 tablespoons of dough for each cookie and place them on the prepared baking sheets, leaving space between each one.
Bake for 10–12 minutes, or until the edges are set and the centers look slightly soft.
Let the cookies cool on the baking sheet for 5 minutes, then transfer to a cooling rack.