Preheat oven to 325 degrees. Line loaf pan with parchment paper and spray with nonstick cooking spray. Set aside.
In a large bowl, stir brownie mix together with eggs, water and oil according to package directions. Pour half into prepared loaf pan. Unwrap white chocolate bar and place in the center. Spread remaining brownie batter overtop. Bake 60-75 minutes or until cooked thoroughly. Cool 20-30 minutes before removing completely.
For the frosting, whip cream cheese, butter, sugar and vanilla together until smooth. Spread over top of loaf. Top with crushed oreos. Slice into pieces and serve.