In a medium saucepan, combine sugar and corn syrup and cook, while stirring, over medium heat until it reaches a golden brown caramel color. Turn off heat, stir in butter, cream, salt and vanilla and stir until combined. Stir in the rice cereal.
Pour mixture over the brownies, using a spatula to smooth over the top. Allow to set almost completely to room temperature for at least 1 to 2 hours.