Cut butter into small cubes. Add butter, brown sugar, and granulated sugar to a large bowl or stand mixer with a paddle attachment. Beat until smooth and creamy, like peanut butter. Scrape sides as needed.
Add eggs, vanilla extract, and coconut extract (if using). Mix until combined.
Add cornstarch, baking powder, baking soda, and salt. Mix briefly. Add flour and mix just until a dough forms.
Add white chocolate chips and chopped macadamia nuts. Mix until evenly combined.
Heat oven to 350°F. Line a sheet pan with a silicone baking mat.
Scoop dough into 40-gram balls (about 2 packed tablespoons). Place 6 dough balls per tray, spaced at least 2 inches apart.
Freeze shaped dough balls on the tray for 10 minutes.
Bake straight from the freezer for 9 to 12 minutes, until tops no longer look wet. Cookies should be slightly underbaked.
Remove from oven and press extra white chocolate chips on top if desired. Let cookies cool on the tray for 5 minutes, then transfer to a cooling rack.
Video
Notes
Note 1: Use cold butter. Softened or melted butter will change the texture.Storage: Best enjoyed the day they’re baked. Freeze dough balls up to 3 months and bake from frozen, adding 2 to 3 minutes.