Preheat the oven to 180°C (350°F) and line a muffin tin with 12 cupcake liners.
In a small bowl combine white vinegar and dairy free milk. The milk may split which is fine. Set aside.
In a bowl, sift the flour, black cocoa powder, bicarbonate of soda, baking powder and salt to combine. Set aside.
In a large mixing bowl, using a whisk or electric mixer, mix together the canola oil, white sugar and vanilla extract until combined.
Slowly add the dry ingredients to the wet, alternating with the milk mixture, beating until the cupcake batter comes together, scraping down the sides of the bowl as necessary.
Spoon the mixture into the muffins tin, ensuring they are only ¾ full before placing them in the oven for 20-25 minutes or until the tops spring back when lightly touched. Let cool completely before frosting.
Make the black cocoa chocolate buttercream. Using a hand mixer or a stand mixer with the paddle attachment fitted, beat dairy free butter and vanilla extract for 1-2 minutes until creamy. Add in 3 cups of the icing sugar and the black cocoa powder and beat on medium until combined. As mixture thickens, add in the dairy free milk a tablespoon at a time. If frosting is too thin, add in an extra ½ icing sugar until it reaches a smooth and creamy consistency. If the mixture is too thick, add in more dairy free milk. Add a pinch of salt to taste if the frosting is too sweet.
Place the buttercream into a piping bag with your favourite tip and pipe buttercream onto cooled cupcakes and top with sprinkles.