Step 1: Preheat your oven to 350°F (175°C).
Step 2: Line a 9x13-inch baking pan with parchment paper.
Step 3: In a large mixing bowl, melt the unsalted butter. Stir in the granulated sugar. Add the eggs one at a time, mixing well. Mix in the vanilla extract.
Step 4: In a separate bowl, whisk together the flour, cocoa powder, and salt. Gradually add to the wet ingredients, stirring until just combined.
Step 5: Fold in the chopped Oreo cookies into the brownie batter.
Step 6: In another bowl, beat the cream cheese until smooth. Gradually add the powdered sugar and mix until combined. Stir in the vanilla extract.
Step 7: Pour the brownie batter into the prepared pan. Dollop the cheesecake mixture over the brownie layer and swirl with a knife.
Step 8: Bake for 30-35 minutes or until a toothpick comes out with a few moist crumbs.
Step 9: Allow to cool for 10 minutes, then lift out using the parchment paper. Cool completely before slicing and refrigerate for at least an hour before serving.
