Preheat the oven to 350 degrees. Line two baking sheets with parchment paper and set aside.

In a small bowl whisk together the flour, baking powder, baking soda and salt. Then set aside the flour mixture.

In a large mixing bowl, cream together the butter, brown sugar and granulated white sugar with an electric hand mixer on high speed until fluffy, about 3 minutes. (If you want to use a stand mixer, use the paddle attachment.)

Add in the egg yolks and vanilla and mix on high speed until pale in color and fluffy, 1-2 minutes.

Add the dry ingredients to the wet ingredients a little bit at a time and mix on low then medium-low speed just until combined.

Add in the white chocolate chips and chopped macadamia nuts and stir them into the dough with a rubber spatula.

Scoop the dough into balls using a 2 tbsp capacity cookie scoop. Arrange the cookie dough balls 6 at a time 2 inches apart on the prepared baking sheets.

Bake the cookies for 10-11 minutes, then let them cool for five minutes on the cookie sheet. Sprinkle with flaky sea salt (if using.) When the cookies are straight out of the oven, use a large circular cookie cutter to give them a perfect shape. Do this by swirling the cookie cutter around each cookie. This will help to push everything together into a perfect circle!

Transfer them to a wire rack to cool for 10-15 more minutes, or until cool enough to handle.

Store left overs in an airtight container for up to three days, or freeze for up to two weeks.