Creating Cookies and Cream Brownies is simple and enjoyable. Just follow these steps:

1. Preheat the Oven: Preheat your oven to 350°F (175°C) and grease a 9×13 inch baking pan.
2. Mix Wet Ingredients: In a large bowl, combine the melted butter, granulated sugar, and vanilla extract. Mix until well blended.
3. Add Eggs: Beat in the eggs, one at a time, ensuring each is fully incorporated before adding the next.
4. Combine Dry Ingredients: In a separate bowl, whisk together the flour, cocoa powder, baking powder, and salt.
5. Combine Mixtures: Gradually add the dry mixture to the wet mixture, stirring until just combined.
6. Incorporate Cookies: Gently fold in the crushed chocolate sandwich cookies and chocolate chips (if using).
7. Pour Batter: Spread the brownie batter evenly into the prepared baking pan.
8. Bake: Place the pan in the preheated oven and bake for 30-35 minutes or until a toothpick inserted in the center comes out with a few moist crumbs.
9. Cool: Once baked, remove from the oven and allow the brownies to cool in the pan for about 10-15 minutes before transferring to a wire rack to cool completely.
10. Slice and Serve: Once cooled, slice into squares and serve as desired.

By following these simple steps, you can create a batch of incredible Cookies and Cream Brownies that everyone will love!