Gather all your ingredients on a clean workspace to streamline your baking process. Preheat your oven to 180°C (350°F) and line a muffin tin with cupcake liners.
In a mixing bowl, combine the dairy-free milk and apple cider vinegar, letting it sit for about five minutes to curdle slightly. Add in the sunflower oil and melted dairy-free butter, mixing until well combined.
In another bowl, sift together the self-raising flour, cocoa powder, baking powder, bicarbonate of soda, and caster sugar. Whisk these dry ingredients together thoroughly to ensure even distribution.
Gradually add the dry mixture into the wet mixture while stirring gently until just combined; be careful not to over-mix as this can affect the texture of your cupcakes.
Spoon equal amounts of batter into each cupcake liner, filling them about two-thirds full. Bake in the preheated oven for approximately 18-20 minutes or until a toothpick inserted comes out clean.
Once baked, allow your cupcakes to cool completely on a wire rack before decorating them with icing made from icing sugar and aquafaba mixed until fluffy. Top each cupcake with crushed Oreos and white chocolate buttons to create cute bat wings!