Whisk together the flour, baking soda, and salt. Set aside.
Using an electric mixer on medium speed, beat the butter, brown sugar, and sugar until light and fluffy. Mix in the whole egg, followed by the egg yolk. Then mix in the vanilla.
Reduce mixer speed to low. Gradually add the flour mixture, mixing just until combined or a few small streaks of flour remain.
Stir in the white chocolate chips and macadamia nuts.
Cover and refrigerate the dough for 1 hour.
Preheat the oven to 350°F (175°C). Line baking sheets with parchment paper or silicone liners.
Drop the dough by 2-tablespoon portions onto the prepared pans. Flatten the tops of each cookie slightly.
Bake one pan at a time for 15 to 18 minutes, or until the cookies are golden brown.
Place the pans on wire racks, and allow the cookies to cool for 5 minutes. Then transfer the cookies from the pans to a wire rack to cool completely.
Notes
To store. Store white chocolate macadamia nut cookies in an airtight container at room temperature for up to 4 days. If you’d like, you can reheat them in the microwave for a few seconds for some fresh-out-of-the-oven warmth.
To freeze. After baking and allowing the cookies to cool completely, place them on a parchment-lined baking sheet and put them in the freezer for about an hour. Once they’re frozen solid, transfer them to an airtight container or zip-top bag, and store it in the freezer for up to 3 months. You can then thaw the cookies at room temperature or heat them in the microwave before serving.