1.Preheat oven to 170°C/150°C fan-forced. Grease deep 20cm ring pan.
2.Sift dry ingredients into medium bowl. Add remaining ingredients; beat with electric mixer on low speed until ingredients are combined. Increase speed to medium; beat about 2 minutes or until mixture is smooth and paler in colour.
3.Pour mixture into pan; bake about 35 minutes. Stand cake in pan 10 minutes before turning, top-side up, onto wire rack to cool.
4.Meanwhile, to make caramel icing; stir butter, brown sugar and milk in small saucepan over heat until sugar dissolves; bring to the boil then simmer, stirring, 2 minutes. Remove from heat, stir in sifted icing sugar.
5.Drizzle warm icing over cake and serve.