Preheat oven to 350F. Line baking sheet with parchment paper or a Silpat.

In bowl of stand mixer using paddle attachment, cream together butter and sugars until smooth and fluffy, about 3-4 minutes on medium high. Add egg and mix just until incorporated. Add vanilla, mixing just until incorporated.

In a separate bowl, whisk together the flour, salt, and baking soda. Gently combine the flour mixture with the butter/sugar mixture until the flour is just mixed in.

Fold in white chocolate chips and macadamia nuts.

Refrigerate for at least a half hour, or at most 3 days. Make golfball sized balls and flatten a bit, or use a medium sized cookie dough scoop. Sprinkle with sea salt, if desired.

Bake for 12-14 minutes, or just until bottoms of cookies are light golden brown. Cookies may seem soft and underdone, but they will set upon cooling.

Cool 5 minutes on baking sheet and use flat spatula to transfer them onto cooling rack.