Combine sugar and corn syrup in a medium saucepan. Place over medium-high heat and stir until the mixture comes to a full boil. Remove from heat and stir in the whole container of peanut butter. Mix well.
Add corn flakes to a large bowl. Pour warm peanut butter mixture over corn flakes and mix well, making sure to coat all of the corn flakes.
Scoop out and form into 1-2 inch balls (I used my hands, but you could use a spoon if you wanted to), and place them on a cookie sheet lined with parchment or wax paper.
If using chocolate, put the chocolate chips in a small bowl and melt in the microwave for about 30-60 seconds. Stir until smooth.
Drizzle the melted chocolate over the cookies.
These cookies are delicious when they are still warm and gooey and equally delicious when they have cooled down and set up a little bit.
Recipe source: Sticky Gooey Creamy Chewy