Preheat oven to 350°F. Line two baking sheets with parchment paper.
In a small bowl, combine flour, baking powder, baking soda and salt. Set aside.
In a large bowl, using a hand mixer or stand mixer, beat butter and both sugars for 2 minutes, scraping the bowl as needed. Add egg and extracts and beat until combined.
Slowly add the flour mixture, beating until just combined. Add ¾ cup each white chocolate chips and macadamia nuts and stir until well combined.
Scoop 2 tablespoon portions of dough and place the dough balls a couple inches apart on the cookie sheets. If desired, top each ball of dough with a few additional white chocolate chips and macadamia nuts (this makes for a prettier cookie).
Bake the cookies for 10-13 minutes, until the edges are beginning to turn golden brown and the very center is still slightly underdone. Rotate the baking sheets halfway through cooking time, if necessary. If your dough balls are smaller or larger than 2 tablespoons, adjust bake time accordingly. Make sure not to overbake. The cookies should still be soft in the center when you remove them from the oven.**
Place the baking sheets on wire racks and allow the cookies to cool completely.
*Optional: I like to press additional macadamia nuts and white chocolate chips onto the top of the cookie dough balls (before baking) to make the cookies look a little prettier. **Bake time: Pulling your cookies from the oven when they are still slightly underdone will result in the perfect texture - soft centers with crisp edges. Oven times vary, and the size of your dough balls may vary slightly from mine. Keep an eye on them. When the edges are set and the very center is still slightly underdone, pull them out and allow them to cool with the baking sheet set on a rack.