Grease and flour pan. Preheat oven to 350 degrees F. In a medium saucepan, melt butter and chocolate over low heat. Pour mixture into a medium bowl. Add sugar, egg and vanilla, and stir with a wooden spoon until combined. Stir in flour. Fill each cavity ¼ full with batter; set pan and remaining brownie batter aside. With an electric mixer, beat cream cheese on medium speed until smooth. Gradually beat in sugar and vanilla. Add egg and beat just until blended. Spoon 1 Tbsp of cream cheese mixture into each cavity. Bake 20 minutes or until wooden toothpick inserted in center comes out clean. Cool in pan for 5 minutes. Invert brownies onto wire rack and cool completely. Rinse pan and repeat process. Makes 24 brownies.