Preheat the oven to 180°C (350°F) and line an 8"x8" baking pan with baking paper and set aside.
Brown the butter by placing the butter in a saucepan over a medium to high heat and melt. Bring the butter to the boil stirring constantly. Boil until the butter becomes a light amber colour and then remove from the heat.
Allow the butter to cool for 5-10 minutes.
Mix the butter and brown sugar together.
Beat in the eggs and vanilla,
Stir through the flour, baking soda and baking powder and finally stir through the white chocolate chips.
Spread into the prepared pan and bake for 20-25 minutes. The top and sides will be golden but the middle will have a slight wobble.