In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar until the mixture is light and fluffy. This step helps create a soft, chewy texture. Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

In a separate bowl, whisk together the all-purpose flour, baking soda, and salt. Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Fold in the crushed Oreos, ensuring they are evenly distributed throughout the dough.

In another bowl, beat the softened cream cheese and granulated sugar until smooth and creamy. Add the egg and vanilla extract, then mix until fully incorporated. Gently fold in the crushed Oreos to add some crunchy texture to the cheesecake filling.

Preheat your oven to 350°F (175°C). Grease and line a 9x13-inch baking dish with parchment paper for easy removal.

Press half of the cookie dough mixture evenly into the bottom of the prepared baking dish to form a solid base. Spread the cheesecake filling evenly over the cookie layer. Crumble the remaining cookie dough over the top, leaving some gaps so the cheesecake filling peeks through.

Place the baking dish in the preheated oven and bake for 30-35 minutes, or until the top is golden brown and set. The edges should be firm while the center remains slightly soft. Remove from the oven and allow the bars to cool completely in the pan.

For best results, refrigerate the Oreo Cheesecake Cookie Bars for at least an hour before slicing. This helps the cheesecake layer set properly, making it easier to cut into clean squares.

Before serving, drizzle melted chocolate over the bars, add a dollop of whipped cream, and sprinkle extra crushed Oreos on top for added indulgence. Enjoy these delicious, rich, and creamy bars with a glass of milk or a cup of coffee!