Bring cream and corn syrup to simmer in heavy medium saucepan, stirring occasionally.
Pour 2/3 cup mixture into bowl.
Add chocolate to bowl and stir until chocolate melts and sauce is smooth.
Add brown sugar to remaining mixture in saucepan and stir over low heat until sugar dissolves.
Increase heat and boil until reduced to sauce consistency, about 2 minutes.
Place 2 scoops of ice cream in each dish.
Pour chocolate sauce over 1 scoop and brown sugar sauce over other.
Sprinkle with toffee and serve.