In a large stand-mixer, cream together the cold butter, brown sugar and sugar for 4 minutes or until creamy.
Add peanut butter and eggs; mix well.
Stir in cornstarch, baking soda and salt until combined.
Add chocolate chips, coconut and flour and mix just until combined.
Layout 2 squares of wax paper and divide dough in half over each. Form your dough into logs that are between 2-3" wide (however wide you want your cookies). Roll wax paper up and freeze dough for at least 4 hours.
When you're ready to bake your cookies preheat oven to 400-degrees.
Unwrap your cookie dough and cut the logs into 3/4"-thick discs. Place on your cookie sheet.
Bake for 9-11 minutes. Cookies should be barely golden on the edges and still look gooey in the middle.
Let cookies rest for at least 30 minutes before eating. Trust me, it's worth the wait!