Preheat oven to 350 degrees F. Line an 8x8-inch square baking dish with foil; coat foil with cooking spray.

Melt the butter in a small saucepan, over medium heat. Whisk in sugar and bring to a boil, whisking frequently; boil 1 minute. Set aside to cool for 5 minutes.

In a small mixing bowl, using a mixer on medium speed, beat together cream cheese, confectioners' sugar and vanilla extract, until well combined, about 1 minute.

In a medium sized mixing bowl, sift together flour, cocoa powder and salt; whisk until combined.
In a large mixing bowl, whisk together eggs, until combined. Whisk in melted butter-sugar mixture until well combined. Stir in flour mixture until just combined, followed by Oreo cookies.

Spread half of brownie batter into baking dish, followed by cream cheese layer; dot the top with remaining brownie batter, and spread evenly, as best as you can. Run a knife through batter to make "swirls".

Bake at 350 degrees F, for 23-28 minutes.

Cool on a wire rack to room temperature before slicing. Lift foil out of baking dish, and slice. For easier slicing, try freezing the brownies for 30-60 minutes.