Microwave the butter until it is almost melted and stir until it is all liquid (you want it to be melted but not hot)
Add the butter and the sugars to a large bowl and using a stand mixer or hand mixer beat together until combined.
Add the egg and vanilla and mix together on high speed for about 30 seconds until mixture is creamy.
Add flour, baking soda & salt and mix together on low speed until incorporated.
Add the macadamia nuts & white chocolate and stir in by hand.
Shape the dough into 12 balls and place on a lined baking tray.
Bake at 180 degrees C for 9-11 minutes, removing from the oven as soon as they are starting to go slightly brown on top.
Allow to cool for 5 minutes on the tray and then transfer to a cooling rack.
Store in an airtight container for 1 week.