Prepare brownie mix as directed on package, adding vanilla. Reserve 1 cup batter. Spread remaining batter in greased 9-inch square baking pan.
Beat cream cheese, sugar and flour in medium bowl with electric mixer on medium speed until smooth. Add egg and raspberry flavor; beat until well blended. Pour over brownie layer in pan. Drop reserved 1 cup batter by spoonfuls over cream cheese layer. Cut through batter with knife several times for marble effect.
Bake as directed on package for 9-inch square pan. Cool in pan on wire rack. Cut into squares.