Preheat oven to 375° F and line three baking sheets with parchment paper.
Slice the cold unsalted butter into ¼ inch cubes and place in the standing mixer, along with the brown sugar and cane sugar. Gradually increase speed and mix on high for 3-4 minutes until there aren't any chunks of butter left.
1 cup unsalted butter, ¾ cup light brown sugar, 1 cup cane sugar
While the butter and sugars are mixing, whisk together the all purpose flour, sea salt, cornstarch, and baking soda in a separate bowl. Set aside.
3 cup all purpose flour, 1 teaspoon fine sea salt, 2 teaspoon cornstarch, 1 teaspoon baking soda
Add the eggs and vanilla extract to the standing mixer and mix on medium speed until creamy and smooth. Scrape down the sides of the bowl halfway through to get an even mix.
2 large eggs, 1 tablespoon vanilla extract
Add the mixed dry ingredients to the standing mixer and mix on the lowest setting until just barely combined. Add the white chocolate chips and chopped macadamia nuts** while the flour is still mixing in--this minimizes the risk of overworking the dough.
1 ½ cup white chocolate chips*, 1 cup chopped macadamia nuts**
Roll the dough out into 15 individual balls, and them spread out 5 to a baking sheet (already lined with parchment paper). Press extra chocolate chips and macadamia nuts into the top of each ball of cookie dough.
Bake each baking sheet separately for about 9-12 minutes each on the middle oven rack, until the cookies start browning on top. They will be very soft--thats okay--they will set once you pull them out of the oven.
After taking the cookies out of the oven, you can use a round cookie cutter or the back edge of a spoon to round out the edges. Let the cookies cool on the pan for about 15 minutes before digging in.Enjoy!