Preheat oven to 400°F. Prepare baking sheets by lining with parchment or silicone mats.
In the bowl of a stand mixer, cream together the sugars and butter. Cream for three minutes. Add the eggs and cream another 2 minutes until creamy and fluffy.
In a separate bowl, combine the flour, cornstarch, salt and baking soda.
Add the flour to the wet ingredients. Mix until just combined.
Toss in the white chocolate chips and chopped macadamia nuts. Mix only until blended.
Scoop cookie dough into golf ball size dough balls. Place on prepared baking sheet.
Bake for 8-10 minutes or until edges just start to brown. Allow to cool on the baking sheet for 5 minutes and then transfer to cooling rack to cool completely.