Preheat the Oven
Preheat your oven to 350°F (175°C). Grease or line a 9×13-inch baking pan with parchment paper.

Make the Cookie Base
In a large bowl, cream together the softened butter, brown sugar, and granulated sugar until smooth. Add the eggs and vanilla extract, beating until fully combined. In another bowl, whisk together the flour, baking soda, and salt. Gradually add the dry ingredients to the wet mixture, stirring until just combined. Gently fold in the crushed Oreos.

Prepare the Cheesecake Layer
In a medium bowl, beat the softened cream cheese and sugar until smooth. Add the egg, vanilla extract, and sour cream, and continue beating until well combined. Gently fold in the crushed Oreos.

Layer the Bars
Press the cookie dough evenly into the prepared baking pan to form the base layer. Pour the cheesecake mixture on top and spread it evenly over the cookie dough. Use a spatula or knife to swirl the two layers together lightly.

Bake the Bars
Bake for 30-35 minutes, or until the cheesecake layer is set and the edges of the cookie bars are golden. A toothpick inserted into the center should come out with a few moist crumbs.

Cool and Slice
Let the bars cool completely in the pan on a wire rack. Once cooled, slice them into squares and serve. For an extra indulgent touch, top with more crushed Oreos or whipped cream.