In a heavy 3-quart saucepan, combine sugar, butter, and evaporated milk; bring to a rolling boil, stirring constantly. Continue boiling, stirring constantly, over medium heat until candy thermometer reaches 234°, or to soft ball stage.
Remove from heat. Add chocolate chips; stir until melted. Add remaining ingredients; beating until well blended.
Pour into greased 13x9x2-inch baking pan.
Cool to room temperature and cut into squares.
*To Test for Soft Ball Stage
A small amount of syrup dropped into chilled water forms a ball, but is soft enough to flatten when picked up with fingers (234° to 240°).
Calories per serving: 353