Marble Brownies

In a large microwave-safe bowl, combine butter and chocolate. Cover and microwave on high for 30-60 seconds; stir until smooth. Beat in sugar, eggs and vanilla. Stir in flour and baking powder until blended. Spread into a greased microwave-safe 8-in. square dish; set aside. In a large microwave-safe bowl, heat cream cheese on high for 30-45 seconds or until softened; stir until smooth. Beat in sugar, egg and vanilla. Spoon over brownie batter; cut through batter with a knife to swirl. Sprinkle with chocolate chips. Shield corners of dish with triangles of foil. Place the dish on an inverted microwave-safe saucer. Cook, uncovered, at 70% power for 8-10 minutes or until a toothpick comes out clean, rotating a half turn after 5 minutes. Heat on high for 1 minute. Remove to a wire rack to cool completely. Store in the refrigerator.