1. Preheat oven to 160C. Over a double boiler, melt your dark chocolate. Remove from heat and while still warm melt in butter, gradually adding and mixing well.
2. Once all the butter is incorporated add in brown sugar and beat well to begin to dissolve sugar.
3. Next, beat in eggs one at a time until incorporated. Follow with the flour and mix well to combine. Add white choc chunks and mix through.
4. Pour mix into a pre-lined 20cm x 20cm brownie tin, top with extra white choc chunks. Bake in oven for 30-35mins or until just set. Remove from oven an allow to cool. Dust with icing sugar, slice and serve.