On medium speed, cream together butter and sugars until light and fluffy, about 2 minutes.
Add eggs, vanilla, baking powder, baking soda, and salt. Beat on medium speed until light and fluffy. About 2 minutes.
Add flour, oats, and coconut. Mix just until incorporated.
Stir in the chocolate chips. Then gently, stir cold cereal in by hand, or on low speed with an electric mixer. Overmixing will smash the cornflakes.
Drop on greased or parchment lined cookie sheet. Bake for 8-10 minutes. The cookies should be golden brown, crispy on the edges, and still a little bit jiggly in the center. Let cookies rest on the baking sheet for a couple of minutes then remove to a wire cooling rack to completely cool.
Notes
Variations:
Butterscotch Chips
White Chocolate Chips
Peanut Butter Chips
Add raisins or dried fruit
Use rice cereal instead of cornflakes.
Storage:
Room Temperature: Store cooled cookies in an airtight container for up to 3-4 days. If the cookies start to dry out add a slice of bread to the container.
Freezer: Set cooled cookies in a single layer on a baking sheet. Freeze until firm. Remove to an airtight container or zip top freezer bag.