Line base and sides of a 22cm-diameter round spring-form cake tin with a double layer of baking paper, allowing a 2cm border above the top of the tin.
Combine golden syrup, caster sugar and oil in a bowl and mix well. Mixture will separate into layers. Set aside.
Sift flour, cinnamon and cloves together into a bowl and set aside.
Bring 1 cup of water to the boil in a saucepan, add bicarbonate of soda and stir gently into sugar mixture until well combined, then stir in ginger. Gradually whisk in sifted flour mixture then add eggs one at a time and mix well.
Pour mixture into prepared tin and bake at 170°C for 60 minutes or until a skewer inserted into cake comes out clean.
Stand in tin for 10 minutes before turning out on a wire rack to cool.
For the icing, whip the butter with the paddle attachment in a mixer. Introduce icing sugar, one cup at a time, beating continuously on a low speed.
Add lemon zest and juice, beating in until smooth. Gradually pour in cream until you achieve a consistency that is easy to spread.
Ice the cake and sprinkle with chopped pistachios. Slice with a hot, clean knife and serve.