Preheat oven to 350 degrees F. Line a baking sheet with parchment paper.
In a large bowl cream the butter and sugars together. Add eggs and vanilla and mix until incorporated.
Add flour, baking powder, baking soda, salt, and oats and stir well to combine. Stir in corn flakes and chocolate chips.
Spoon large tablespoons of the dough onto prepared cookie sheet.
Bake at 350 degrees F for 10-12 minutes or until set on the top.
