In a large bowl, using a hand mixer or a stand mixer, cream together the butter and cream cheese until smooth on medium speed, about 1 minute. Add the powdered sugar in the bowl a little at a time until fully mixed, and scrape down the sides as needed. Add in the egg and vanilla, and mix to combine.

In a small bowl, whisk together the baking powder, salt, and flour. Add to the mixer a little at a time until fully incorporated, and scrape down the sides as needed. Add in the crushed cookies and mix until just combined.

Cover and place the cookie dough in the fridge for at least 2 hours. The dough must be very cold before baking or the cookies will spread.

Preheat the oven to 350°F. Place 1 tablespoon-sized ball of cookie dough onto a parchment-lined sheet tray. You can roll the cookie dough into balls for a more uniform look. Bake for 9-10 minutes until they are just set. You know they are ready when they don’t look wet anymore. Let them cool completely on the sheet tray.