Preheat oven to 350° F. Line a large baking sheet with parchment paper. Line a 9 or 10-inch spring form pan with a circle of parchment paper and spray the interior with non-stick cooking spray. Place on the baking sheet. In 2 quart saucepan combine the butter and chocolate chips. Cook over low heat, stirring occasionally, until melted (4 to 6 minutes). Remove to a medium bowl and stir in sugar, all-purpose flour, eggs, salt, baking powder, vanilla extract, chocolate chips, white chocolate chips and caramel bits. Spoon batter into pan. For the cream cheese filling, in a small bowl or food processor, blend sugar, cream cheese, egg, flour and vanilla until smooth. Spread filling over brownie mixture and swirl with a knife. Bake for 30-35 minutes or until brownies are just set. Chill an hour or two. Remove from pan and drizzle on melted chocolate and caramel. Cut into wedges to serve.