These fudgy dark chocolate brownies have thick layer of Oreo cheesecake with big chunks of Oreos. It tastes like Cookies 'n Cream ice cream, but even better because: brownies!
Make the cheesecake batter. Beat soft cream cheese in a medium bowl with an electric hand mixer or spatula until smooth. Add sugar and vanilla and beat until glossy. Beat in egg until well incorporated. Mix in white chocolate and sour cream, then fold in Oreo cookie crumbs and broken Oreos.
Make the brownie batter. Combine chocolate and butter in a saucepan over very low heat and stir constantly until melted and smooth. Be careful not to burn the chocolate so be patient and keep the heat on low. The butter should help protect the chocolate from burning. You can also melt in the microwave at 50% power in short bursts with frequent stirring.
Pour the melted chocolate mixture into a large bowl. Add sugar and eggs and mix well until the batter is smooth and tightens up and becomes glossy. Mix in salt and vanilla. Sprinkle flour over the surface and fold it in until evenly combined.
Spread the brownie batter evenly into prepared pan, reserving about 3 tablespoons (45ml). Spread the cheesecake batter evenly over the brownie batter in the pan, then spoon teaspoons of reserved brownie batter randomly over top and swirl it in with a knife. Sprinkle a few extra Oreo cookie crumbs on top.
Bake for 27-32 minutes until puffed and the cheesecake is set in the middle and lightly golden. Transfer pan to a wire rack and let cool completely in the pan. Refrigerate for at least 1 hour before slicing with a hot dry knife.