In a small saucepan, add butter and heat on medium low. Let butter melt, then cook for around 5-7 minutes, swirling the saucepan occasionally. Butter will bubble and solids will collect at the bottom of the saucepan. Be sure to watch the butter carefully, for it can go from brown to burnt in seconds!

When the butter solids turn golden brown, immediately remove brown butter from heat and pour into a bowl. Let butter cool completely before using it to make the cookies. You'll want the butter to be room temperature when working with it; so either let the butter cool at room temperature for a few hours, or let cool in the refrigerator and bring back up to room temperature when you're ready to make the cookies.

Add room temperature butter to either a large bowl or the bowl of a standing mixer. Use a mixer to whip the butter until it is fluffy. Add brown and white sugars, and cream sugars into the butter until smooth.

Add egg and vanilla extract to the creamed butter and sugar, and mix until smooth.

In a large bowl, whisk together flour, salt, and baking soda. Add flour mixture to wet ingredients, about a third cup at a time, until dry ingredients are fully incorporated.

Fold in white chocolate chips and macadamia nuts.

Chill dough in fridge for 30 minutes.

Using a spoon or cookie scoop, scoop the dough into 1 tablespoon balls. Place about 2" apart on the baking sheet.

Bake for 10-13 minutes, or until cookies have spread and are golden brown on the edges.