Preheat the oven to 350° Fahrenheit. Line a baking sheet with parchment paper, and set aside.
Make the brown butter by heating 8 tablespoons butter in a saucepan over medium heat until brown bits form. Try not to walk away as it can burn very quickly. Immediately remove the butter from the heat, and set it aside to cool completely.
8 Tablespoons brown butter
In a large mixing bowl, whisk together the flour, baking soda, and salt.
2 cups all-purpose flour, 1/2 teaspoon baking soda, 1/2 teaspoon salt
In a separate large bowl, whisk together the brown sugar, white sugar, softened butter, and cooled brown butter until smooth. Add the whole egg, and beat for 1 minute. Scrape down the sides of the bowl, and add the egg yolk and vanilla. Beat for 1-2 minutes or until fluffy.
3/4 cup packed light brown sugar, 3/4 cup granulated sugar, 8 Tablespoons unsalted butter, 1 large egg, 1 egg yolk, 1 teaspoon vanilla extract
Add the dry ingredients to the bowl with the wet ingredients. Stir until no streaks of flour remain. Be careful not to overmix!
Gently fold in the white chocolate and macadamia nuts.
10 ounces white chocolate chip, 1 cup macadamia nuts
Use a large cookie scoop to portion out the dough into equal-sized portions. Arrange them on the prepared baking sheet.
Bake for 9-10 minutes or until the edges are golden brown.
Transfer to a cooling rack.
Store at room temperature for up to 1 week.