Preheat the oven to 160°C (320°F). Line 3x20 cm (8 inch) cake pans with with baking paper or brush with oil.
Add all the dry ingredients to a large mixing bowl or stand mixer. Mix until there are no lumps. Add all the wet ingredients to the bowl and mix until combined.
Evenly divide the cake batter into the 3 cake tins. Bake for 35-40 minutes or until a skewer can be inserted into each cake and it comes out clean. Allow the cakes to cool in the tins for 20 minutes then place them on a wire rack.
To make the frosting:
Add the vegan butter to a stand mixer with the whisk attachment. If you don't have a stand mixer, add the butter to a large bowl and use an electric hand mixer. Beat on high speed for 3 to 5 minutes until the butter has increased in size and turned pale yellow or white.
Add the powdered sugar and vanilla to the mixer or bowl. Beat on low speed for 30 seconds or until the sugar is fully incorporated. Increase the speed to high and beat for another 5 to 10 minutes or until the buttercream is light and fluffy.
Using a serrated knife, slice the domes off the cakes, ensuring each is as flat as possible.
Place one cake layer on a serving plate and generously spread a layer of frosting on the top. Gently place the next cake layer on the frosting making sure it is level. Repeat until all layers of the cake have been used up.
Spread a thin layer of icing on the sides of the cake and use a cake scraper to level it out. Messily spread the remainder of the frosting on the top of the cake.
Place gingerbread people and cherries on the cake as desired.
Serve immediately. If you want to serve the cake later, put the frosted cake in an airtight container in the fridge without the gingerbread people and cherries. Decorate the cake just before serving*. Store the cake in the fridge for up to 5 days or in slices in the freezer for up to 1 month.
* The gingerbread people are best stored away from the frosted cake so they remain crisp. The sugared cherries need to be stored away from the cake as well so they maintain their sugary appearance.