1.Line base and side of steamer basket of 2.5-litre (10-cup) rice cooker using a single round of baking paper, large enough to extend 2cm above side of basket. Pleat paper to fit neatly around side of basket.
2.Combine butter, melted chocolate, choc bits, caster sugar, eggs and flour in large bowl; mix well. Spread mixture into basket. Pour 1½ cups boiling water into rice cooker. Place basket in cooker; secure lid. COOK about 20 minutes or until cooker automatically switches to KEEP WARM.
3.Remove basket from cooker; cool brownie in basket before cutting into 12 squares. Serve dusted with sifted icing sugar.