Prep. Preheat oven to 375°F. Line a baking sheet with parchment paper and set aside.
Mix the Dry Ingredients. In a medium bowl, whisk together the 2 1/4 cups flour, 1 teaspoon baking soda, and 1 teaspoon salt. Set aside.
Cream Butter and Sugars. In the bowl of a stand mixer or using a hand mixer, beat the 2 sticks unsalted butter, 3/4 cup brown sugar, and 1/2 cup granulated sugar together on medium speed for 2–3 minutes until light and fluffy. Scrape down the sides of the bowl as needed.
Add Wet Ingredients. Reduce to low speed and add the 2 eggs, 1 extra egg yolk, and 2 teaspoons vanilla extract. Beat until just combined, about 1 minute.
Combine. Add the flour mixture to the wet ingredients and mix on low speed until just incorporated — stop as soon as no dry streaks remain. Mix in the bag of white chocolate chips and 1 cup macadamia nuts.
Chill. Cover and chill the dough in the refrigerator for at least 30 minutes and up to 4 days. If chilling for longer than 2 hours, allow to sit at room temperature for at least 20-30 minutes before rolling and baking because the dough will be quite hard.
Scoop and Bake. Use a medium cookie scoop to portion dough balls onto the prepared baking sheet, spacing them about 2 inches apart. Bake 10–12 minutes, until the edges are golden brown but the centers still look slightly underdone — they will firm up on the cooling rack. For crispy edges and soft centers, pull them at 10 minutes. For crispier cookies throughout, go the full 12.
Cool. Let cookies cool on the baking sheet for 5 minutes before transferring to a cooling rack. This prevents the soft centers from breaking apart.