In heavy saucepan melt butter. Add evaporated milk, sugar, and coffee. Bring to a rolling boil, stirring constantly, until temperature reaches 235 degrees. Remove from heat and add chips and the bittersweet chocolate, stirring until melted. Add marshmallow cream, stir until mixed in. Stir in vanilla. Pour into lightly greased 9 x 13 pan. Cut into squares when cool.