This classic frosted carrot cake is made with a surprising vegan ingredient that guarantees a moist sponge every time.
1. Heat the oven to 180C/fan 160C/gas 4 and line two 18cm cake tins with baking paper.
2. Whisk together the oil, sugar, vanilla and orange zest in a large bowl, until the sugar begins to dissolve.
3. In a measuring jug, combine the soy milk and the cider vinegar. Whisk well and set aside (the milk will appear to split or thicken but don’t worry if it does).
4. In a small bowl, mix together the ground psyllium husks and 3 tbsp of water. Allow to thicken for 20 seconds before adding to the brown oil and sugar mixture. Whisk well for 30 seconds – the mixture should come together and the oil should no longer be separated from the sugar.
5. Little by little, add the thickened soy milk to the oil and sugar mixture, whisking all the time. In a bowl, sift together the flour, baking powder, bicarbonate, 2 tsp of the cinnamon, and all of the nutmeg, ginger and salt. Stir together.
6. Add the flour mixture to the wet mixture along with the grated carrots and 70g of the chopped walnuts. Mix until just combined.
7. Divide the batter between the two prepared cake tins and bake in the oven for 25-30 minutes. Before removing from the oven, test with a toothpick in the centre of each cake it should come out clean. Allow the cakes to cool completely in their tins on a wire rack.
8. While the cakes are cooling, make the frosting. In the bowl of a stand mixer fitted with the whisk attachment or in a bowl using electric beaters, beat the vegan butter and cream cheese until smooth and fluffy. Add the vanilla bean paste and beat again to combine.
9. In another bowl, sift the icing sugar. With the stand mixer on low, add the icing sugar a heaped spoonful at a time (if you add it all at once the frosting will split). You may not need to add all the icing sugar, so keep adding until the frosting is thick, smooth and whipped. The more sugar you add, the thicker the frosting will become.
10. To assemble the cake, remove the cooled cake layers from the tins. Carefully apply a generous layer of frosting on top of one layer. Top with the second layer, followed by the remaining frosting, then use a pallet knife to lightly ice the sides of the cakes, leaving a ‘naked’ finish, with the sponges still slightly exposed. Before serving, sprinkle the cake with the remaining ½ tsp of cinnamon and the roughly chopped walnuts.