Line a baking sheet with parchment paper.
Sift together the all-purpose flour, baking soda, baking powder, and salt into a bowl and set aside.
Whisk together the cooled melted unsalted butter, granulated sugar, brown sugar, vanilla, and eggs until combined.
Add the sifted dry ingredients to the wet ingredients and mix until cookie dough is formed.
Fold in the white chocolate and chopped macadamia nuts.
Using a 2 Tbsp cookie scoop, divide the batter into 22-24 cookie scoops, adding to the baking sheet.
Chill the cookie dough for 30 minutes.
Preheat the oven to 350°F and line another large baking sheet with parchment paper.
Roll the dough scoops into round balls, placing 1-2 inches apart from each other onto the baking sheets. (Depending on the size baking sheets you use you might need multiple or bake in batches.)
Bake the macadamia nut cookies at 350°F for 12 minutes or until slightly golden. Remove from the heat and top with flakey salt.
Cool for 5-10 minutes and then serve warm or completely cool.