Crush the Oreos in a zip-lock bag using a rolling pin until you have small chunks and rough crumbs. Keep some bigger pieces for texture. Set this aside. In a separate medium bowl, whisk together the flour, baking powder, baking soda, salt, and cinnamon. Set this bowl aside.

In a large bowl, beat softened butter with brown sugar and white sugar using a hand mixer or stand mixer on medium speed for 2 to 3 minutes. The mix should look light and fluffy. Add the eggs one at a time, mixing well after each addition. Then, add the vanilla extract and mix until combined.

Add the Dry Ingredients: Mix the flour mixture into the butter mixture in two parts. Use low speed until no dry flour is visible. Don’t overmix; stop as soon as the flour is gone. Use a spatula to gently fold in the crushed Oreos, keeping some bigger pieces for texture.

Cover the bowl with plastic wrap and refrigerate for at least 30 minutes. Chilling overnight is better. This helps the cookies keep their shape while baking.

Preheat the oven to 350°F. Line your baking sheets with parchment paper. Use a cookie scoop to make dough balls of about 1.5 tablespoons each. Space them 2 inches apart on the baking sheet. Bake for 10 to 12 minutes. The edges should be set and lightly golden, while the centers look slightly underdone.

Let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack. Allow them to cool completely before adding frosting. They will firm up while cooling.

Beat cream cheese and butter together until smooth. Add the powdered sugar and mix in vanilla and cinnamon, if you want. Mix until creamy and fluffy. Spoon or pipe the frosting onto each cooled cookie.