Method (Cake)

1. Preheat your oven to 180ºC fan and line an 8 x 8 inch square cake tin with greaseproof paper. Allow the paper to hang over the tin slightly, this makes it easier to remove the cake when baked.
2. In a bowl, combine the dairy-free milk with the apple cider vinegar and whisk until fully combined. Set aside for 10 minutes to curdle. This creates a vegan ‘buttermilk’.
3. In a large mixing bowl, sift the flour, pumpkin spice blend, sugar, baking powder and bicarbonate of soda. Mix well to combine. Add the vanilla, pumpkin purée and oil into the ‘buttermilk’ and whisk to combine.
4. Add the wet ingredients into the dry ingredients and mix just to combine. 
5. Spoon the batter into the lined tin. Level it out with the back of a spoon or offset spatula.
6. Place the cake into the middle of the preheated oven and bake for around 25-30 minutes. You will know it is done when you put a knife or skewer down the middle of the cake and it comes out clean and it’s springy to the touch. If batter comes off on the skewer, it needs more time to bake. To prevent burning, top the cake with some greaseproof paper then return back into the oven.
7. Allow the cake to cool in the tin for 10 minutes then carefully transfer onto a cooling rack. Allow to cool fully before frosting. You can even place the cake in a sealed container once cool then frost the day after. It’s a very light sponge so be careful with it when removing from the tin.

Method (frosting)

1. In a large mixing bowl, add in the dairy-free butter and cream cheese, whip until creamy. I use a stand mixer with a balloon whisk attachment, a hand mixer will work great too.
2. Sift in the icing sugar and vanilla. Whip on high speed for a couple of minutes to incorporate it. Add a splash of dairy-free milk to get it to a smooth consistency. 
3. Remove 4 heaped tablespoons of the buttercream and separate into three bowls. Leave the majority of the buttercream white, colour one bowl with orange food colour, the 2nd with green and the third with some cocoa. You don’t need much coloured frosting for this, only for the pumpkins on top, so only use what you need. The rest of the frosting can be swirled to the top of the cake.
4. Transfer the orange buttercream into a piping bag fitted with a small round-tip nozzle. Add the green and brown into separate piping bags with a tiny bit of the tip snipped off.
5. Using a pallet knife, carefully spread and swirl the white frosting  over the entire cake.
6. Pipe mini pumpkins with the coloured buttercream (watch the video tutorial here).
7. Decorate with a sprinkle of chopped walnuts (optional).
8. Slice and serve.