Add the softened butter, cream cheese, brown sugar, and granulated sugar to a large mixing bowl with hand mixer or the bowl of a stand mixer with paddle attachment. Beat until light and creamy.

Mix in the sourdough discard, egg, and vanilla extract until smooth and well combined.

In a separate bowl, whisk together the all-purpose flour, baking soda, baking powder, cornstarch, and salt.

Slowly add the dry ingredients to the wet ingredients. Mix just until the flour is incorporated. Don't overmix the dough.

Fold in the crushed chocolate sandwich cookies and white chocolate chips. Try not to crush the cookie pieces too much as you mix. Place dough in fridge for 30 minutes to 3 days. For long fermentation, place dough in fridge for at least 2-3 days.

Use a cookie scoop to portion the dough onto a parchment lined baking sheet, leaving space between each cookie. Place an extra chunk of oreo pieces on top. Optional, but pretty.