In a small saucepan over medium-low heat, melt the butter. Keep cooking and whisking until the butter turns golden brown and has a nutty smell. Once it’s browned, immediately pour it into a bowl to cool and solidify. To speed up the cooling, place the bowl of butter into a larger bowl filled with ice and whisk until solid.

While the butter cools, whisk together the flour, baking soda, and salt in a mixing bowl. Set aside.

In a large mixing bowl, beat the cooled brown butter with the granulated and brown sugars until smooth and creamy. Add the eggs and beat until light and fluffy. Add the sourdough discard and vanilla extract, mixing until fully combined.

Gradually add the dry ingredients to the wet ingredients, mixing until a thick dough forms. Gently fold in the white chocolate chips and chopped, toasted macadamia nuts.

For the best flavor and texture, cover the dough and refrigerate for at least 1 hour (or up to 48 hours). If you're short on time, you can bake the dough right away if it’s not overly soft. When ready to bake, preheat your oven to 350°F. Line a baking sheet with parchment paper.

Drop heaping tablespoons of dough onto the prepared baking sheet, leaving about 2 inches between each. For a nicer appearance, press a few extra white chocolate chips on top of each dough ball if desired. Bake for 9-11 minutes, until the edges are golden brown and the centers are just slightly underbaked.

Allow the cookies to cool on the baking sheet for 5 minutes, then transfer them to a wire rack to cool completely.