For the cake

1. Pre-heat the oven to 170 c / 325 f and grease and line 2 x 20 cm tins
2. Add the lemon juice to the milk to sour it. (Alternatively you could use buttermilk).
3. Add the orange juice to the milk also.
4. Place the sugar, eggs, soured milk, oil and vanilla extract in a free-standing mixer and beat to combine.
5. In a separate bowl combine the flour, bicarb, baking powder, cinnamon, ginger and salt.
6. Slowly add the dry ingredients to the wet and continue to beat until smooth.
7. Add the grated carrots and chopped walnuts then stir by hand to distribute evenly.
8. Pour into the two tins and level the mixture
9. Place in the preheated oven for about 40 min or until a cake tester / knife comes out clean.
10. Turn out onto racks to cool

For the frosting

1. In a free-standing mixer beat the icing sugar and butter together until combined.
2. Add the cream cheese and beat at a medium speed for about 5 minutes until the mixture is light and fluffy. Be careful not to over beat the frosting or the cream cheese will split and become runny.
3. Use a palate knife to spread the frosting evenly and add extra chopped walnuts on top for decoration