Spray a roasting pan with non-stick cooking spray.
Place the cereal into the pan.
In a 3-quart saucepan combine brown sugar, butter and light corn syrup; cook over medium heat until the mixture comes to a boil (about 8-10 minutes) continue cooking stirring constantly for 1 minute; remove from heat, then add in baking soda and mix well.
Pour the syrup mixture over the cereal in the pan; toss gently until well coated.
Bake at 250 degrees for 40-50 minutes stirring every 15 minutes or until the coating is set.
Spread the mixture onto waxed paper; cool for 10 minutes then break apart.