Method
Step 1:
Preheat oven to 160°C. Line a greased 22cm-square cake tin with baking paper.
Step 2:
Place dark chocolate and butter in a metal bowl over a saucepan of simmering water and stir until melted. Set aside to cool slightly.
Step 3:
Place eggs and sugar in a mixing bowl and whisk to combine. Add cooled chocolate mixture, cocoa, flour, baking powder, vanilla and salt. Stir to combine.
Step 4:
Fold through milk and white chocolate chunks. Transfer mixture to prepared tin and bake for 40 minutes or until cooked through but still slightly fudgy in the centre. Serve dusted with icing sugar.