Pre heat a fan forced oven to 170℃
Start by chopping the macadamia nuts into quarters.
Next chop the white chocolate into a similar size to the quartered nuts and set aside both.
In a mixing bowl place butter and sugar and beat on high for a minute until well combined.
Add vanilla and egg and then beat again for 30 seconds.
Next add the baking powder and flour and beat on low speed until the flour is well incorporated.
Add macadamia nuts and white chocolate and use a wooden spoon to mix into the dough evenly.
Turn the dough out on a work surface and bring the dough together with your hands and shape it into a large ball. Then pop back in the mixing bowl.
Line one or two baking trays with baking paper (depending on their size).
Roll the dough into smaller balls (should be the size of golf balls) using your hands and then place them on the baking tray (make sure not to overcrowd the trays).
Gently press down on each ball with the back of three fingers to flatten them slightly.
Place trays into the oven on the middle shelves and bake for 20 minutes, rotating the tray at 10 minutes so that the cookies bake evenly.
After 20 minutes remove from the oven and allow cookies to cool completely on the tray.