Preheat your oven to 175°C/350°F Line your cupcake tin with the cupcake liners. The recipe makes 12 cupcakes. Take your vegan butter out of the fridge to soften. Weigh all of your ingredients and set aside.
The wet ingredients
Measure the non-dairy milk, I used soy milk because it's already a creamy milk but you can use any non-dairy milk you want! Add in the apple cider vinegar. Mix and set this aside to curdle for a couple of minutes. Then add this to a bowl, you will notice that the milk has gotten thick and creamy! This is good. Then add in the vanilla and oil. I used sunflower oil but you can use any neutral oil you want. Whisk to combine using a hand mixer or a regular whisk. Then add in the sugar and whisk until the sugar is dissolved. Set this aside.
The dry ingredients
Sift the flour and baking powder into a bowl. Add in the baking soda and salt. Whisk to combine. Then add in the non-dairy milk mixture from before and mix really well until everything is combined. Do this using a whisk or a hand mixer. It should resemble American pancake batter, thick and not too liquid. Now add in the black food colour. Add enough to make the batter pitch black. Mix until the entire batch of batter is black.
Divide the batter equally into the cupcake tin and liners. Then bake for 25 minutes. You can also check if they're done by using the toothpick method. If you stick a toothpick in the center of the cupcake and it comes out clean, they're done. But I suggest waiting the full 25 minutes. Let them cool completely before piping on the buttercream.
Add the soft vegan butter to a bowl, or if you're using a stand mixer use the bowl that comes with the mixer. Beat the butter using a hand mixer or a stand mixer until the butter is fluffy and is light of colour. Scrape down the sides of the bowl with a silicone spatula occasionally. Then add a splash of vanilla extract and mix again with your mixer. Once combined, gradually add the icing sugar. Every time you add in the sugar, start your mixer slowly at first so it doesn't create a huge cloud. Once the sugar is incorporated you can put the mixer on a higher setting. Also scrape down the sides every so often. Do this until all of the sugar is used. Then add in enough orange food colouring until the buttercream is bright orange.
Put the buttercream in your piping bag and to the best of your ability pipe the buttercream on the cupcakes. Alternatively you can just use a knife to spread the buttercream on the cupcakes. This is way easier as well! Optional: sprinkle on your Halloween themed sprinkles, but this is totally not necessary if you can't find any vegan sprinkles!