Prepare: Preheat your oven to 175°C (347°F). Line the base of three 6" cake tins or two 8" cake tins with a circle of parchment paper and spray the sides with oil spray.Add the soy milk and apple cider vinegar to a jug, stir, and allow to sit for 10 minutes.
Mix the wet ingredients: Add the sunflower oil, vanilla extract, and orange zest to the jug and mix using a fork.
Mix the dry ingredients: Add the plain flour, granulated sugar, soft brown sugar, baking powder, baking soda, cinnamon, nutmeg, ginger, and sea salt to a large mixing bowl, whisk, and set aside.
Make the batter: Add the wet ingredients to the bowl with the dry ingredients and whisk carefully to combine. Do not overmix the batter. Fold the grated carrots and chopped walnuts in until just combined.
Bake: Divide the batter into the lined cake pans. For 6" cakes - bake for 30-35 minutes, for 8" cakes - bake for 25-30 minutes. Check they are ready by inserting a skewer, it should come out clean. Allow the cakes to cool in the tins for 15-20 minutes and then carefully turn them out onto a cooling rack to cool further.
Prepare a batch of vegan cream cheese frosting according to the recipe. For an orange version, first, reduce the juice in a saucepan until it is down to 50ml. Then cool it, and slowly drizzle into the buttercream while whisking during the final stage.
Assembly: Place a tiny amount of frosting on a cake turntable and secure the first sponge layer on top of it. Use an offset spatula/pallet knife to spread a layer of frosting on top of the sponge. Add the next layer of cake and repeat with another layer of frosting. Top with the final layer of cake. Use the remaining frosting to coat around the sides on top of the cake and smooth everything out with a cake scraper.
Decorate with chopped walnuts, carrots, carrot tops, and/or orange slices.
Storage: This cake is best served at room temperature to ensure it keeps its fluffy consistency. If you don't plan on eating it all in a day or so, seal it in an airtight container and refrigerate it for up to 5 days. Then remove the cake from the fridge about 1-2 hours before serving to bring it back to room temperature.
Nutritional information is based on the cake without buttercream
As with all baking, measuring with a kitchen scale will always give you the most accurate results, therefore I highly recommend that you measure the recipe in grams.
Preheat your oven properly as the oven temperature affects the texture, flavor, and browning of the cake. I usually aim to preheat the oven a good 30 minutes before baking.
Use freshly grated carrots for the best flavor as well as provide moisture that can be lacking from pre-packaged grated carrots.