1.Preheat oven to 180°C/160°C fan-forced. Grease 20cm x 30cm lamington pan; line base and long sides of pan with baking paper, extending paper 5cm above edges of pan.
2.Beat butter and sugar in small bowl with electric mixer until light and fluffy. Add flour and ginger; beat on low speed until just combined.
3.Spread mixture evenly into pan; bake about 15 minutes or until browned lightly. Cool to room temperature in pan.
4.For the macadamia topping, combine butter, syrup and icing sugar in small saucepan; stir over heat until mixture is smooth. Stir in nuts and ginger.
5.Spread hot macadamia topping evenly over cooled base; bake in oven about 10 minutes. Cool in pan before cutting into 16 pieces
Make sure that the base has completely cooled to room temperature before spreading on the hot macadamia topping.Note