Melt butter and chocolate over low heat, remove and cool.
Mix sugar, eggs, flour and vanilla. Then add cooled chocolate/butter. Mix well.
In a separate bowl, cream butter and cream cheese, add sugar, blend in egg, add flour and vanilla. Mix well.
In a well buttered and floured baking pan, pour 2/3 of chocolate brownie mix, then layer with cream cheese mix and drizzle on rest of chocolate brownie mix and bake at 350 degrees for 25 to 30 minutes.