Place chocolate chips, corn syrup and butter in microwave-safe bowl.
Microwave uncovered on high for about 60-90 seconds and stir until smooth.
Stir in vanilla.
Pour over cereal mixture and mix well.
Spoon into greased 13x9 inch pan.
Refrigerate for 30 minutes and cut into squares.
Notes
Mixing Technique: When combining the melted chocolate mixture with the cereal and sugar, use a gentle folding motion rather than stirring vigorously. This helps to evenly coat the cereal with the chocolate mixture while maintaining the crispiness of the cereal.
Uniform Thickness: After spreading the mixture into the 13x9-inch pan, use a spatula or the back of a spoon to press it down firmly and evenly. This ensures that the bars have a uniform thickness, making them easier to cut into neat squares once chilled.
Chilling Time: Allow the bars to chill in the refrigerator for at least 30 minutes before cutting into squares. This chilling time allows the chocolate mixture to set and firm up, making it easier to cut the bars without them falling apart. For cleaner cuts, run a knife under hot water before slicing through the chilled bars.